Ready to supercharge your AI agents?

Install any skill in seconds. Free to start, no credit card required.

UI Feature Implementation · marcus | DecimalAI

Frontendby marcus

UI Feature Implementation

Implementing UI/UX features in sidecar including modals (internal/modal library), keyboard shortcuts, mouse support, scrolling, pill/tab rendering, and pane resizing.

Never made a case worseMaintained

SkillScore

SkillScore91/100

Test results 91

Safety

3/3 safety checks passed

Code scan
Intent
Content

What it changes

36%91%of test cases passed +55 pts

Without skill8 of 22

With skill20 of 22

12 fixed8 passed either way2 still failing0 broke

Measured on gemini-3.6-flash9/2/2026v5

Track record

Agent runs: 0; All time

See one task, with and without the skill

One test taskIn a plugin modal where content depends on asynchronously fetched git branch data, what should happen in the plugin Update method when branch data arrives to ensure the modal displays refreshed content?

Without the skillMissed

With the skillPassed

Same model, same task. Answers are capped and redacted.

Use this skill

Your agent runs on

Adds every file the skill has, pinned so you can update it. No account needed.

pip install "decimalai>=0.15"
decimalai skills add marcus-ui-features
claude --plugin-dir "$(git rev-parse --show-toplevel 2>/dev/null || pwd)/.agents"

The same install from Python, for a notebook or a setup script.

Install

pip install "decimalai>=0.15"

Add the skill

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

print("Added. Start Claude Code with the command below.")

Start Claude Code with it

claude --plugin-dir "$(git rev-parse --show-toplevel 2>/dev/null || pwd)/.agents"

Type these in a Claude Code session. No account or API key. It writes the skill and any files it bundles, and asks first when its safety rating isn't Passed.

Add the DecimalAI plugin, once

/plugin marketplace add decimal-labs/decimalai-claude-plugins
/plugin install decimalai@decimalai

Install this skill

/decimalai:install marcus-ui-features

The plugin needs python3 and curl on your machine.

No Python or account. Claude Code picks it up in its next session.

Save it into your project

curl -fsSL --create-dirs -o .claude/skills/marcus-ui-features/SKILL.md https://app.decimal.ai/s/marcus-ui-features/SKILL.md

Copy SKILL.md

Save it in your project, as

.claude/skills/marcus-ui-features/SKILL.md

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Claude Code docs

agent_config() hands your agent the skill. With no DecimalAI key it reads your project's files and sends nothing. Needs SDK 0.27 or newer.

Install

pip install "decimalai[claude-agent-sdk]"
decimalai skills add marcus-ui-features

Add it to your agent

import asyncio

from claude_agent_sdk import ClaudeAgentOptions
from decimalai.claude_agent_sdk import agent_config

# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

async def main():
    question = "Hello!"
    async with support.run(question) as run:  # one user message, one run
        async for message in run.query(options=ClaudeAgentOptions(max_turns=6)):
            print(message)

# In a notebook or async code: await main()
asyncio.run(main())

Prefer its own loader? ClaudeAgentOptions(plugins=[skills_plugin()], skills="all") reads the same folder. Use one or the other: a skill delivered both ways reaches the prompt twice.

The same install from Python, for a notebook or a setup script. agent_config() hands your agent the skill. With no DecimalAI key it reads your project's files and sends nothing. Needs SDK 0.27 or newer.

Install

pip install "decimalai[claude-agent-sdk]"

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

import asyncio

from claude_agent_sdk import ClaudeAgentOptions
from decimalai.claude_agent_sdk import agent_config

# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

async def main():
    question = "Hello!"
    async with support.run(question) as run:  # one user message, one run
        async for message in run.query(options=ClaudeAgentOptions(max_turns=6)):
            print(message)

# In a notebook or async code: await main()
asyncio.run(main())

Prefer its own loader? ClaudeAgentOptions(plugins=[skills_plugin()], skills="all") reads the same folder. Use one or the other: a skill delivered both ways reaches the prompt twice.

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

import asyncio
from pathlib import Path
from claude_agent_sdk import ClaudeAgentOptions, query

skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
options = ClaudeAgentOptions(system_prompt=f"You are a helpful agent.\n\n{skill}", max_turns=6)

async def main():
    async for message in query(prompt="Hello!", options=options):
        print(message)

# In a notebook or async code: await main()
asyncio.run(main())

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Claude Agent SDK docs

agent_config() hands your agent the skill. With no DecimalAI key it reads your project's files and sends nothing. Needs SDK 0.27 or newer.

Install

pip install "decimalai[openai-agents]"
decimalai skills add marcus-ui-features

Add it to your agent

from agents import Agent, Runner
from decimalai.openai_agents import agent_config

# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

agent = Agent(
    name=support.name,
    instructions=support.instructions,  # your prompt, then the skill list
    tools=[*support.tools],             # your tools, then load_skill
)
# In a notebook or async code: result = await Runner.run(agent, "Hello!")
result = Runner.run_sync(agent, "Hello!")

Using SandboxAgent? capabilities=[Shell(), decimalai.openai_agents.sandbox_skills()] points its own loader at the same folder.

Install

pip install "decimalai[openai-agents]"

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

from agents import Agent, Runner
from decimalai.openai_agents import agent_config

# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

agent = Agent(
    name=support.name,
    instructions=support.instructions,  # your prompt, then the skill list
    tools=[*support.tools],             # your tools, then load_skill
)
# In a notebook or async code: result = await Runner.run(agent, "Hello!")
result = Runner.run_sync(agent, "Hello!")

Using SandboxAgent? capabilities=[Shell(), decimalai.openai_agents.sandbox_skills()] points its own loader at the same folder.

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

from pathlib import Path
from agents import Agent, Runner

skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
agent = Agent(name="support", instructions=f"You are a helpful agent.\n\n{skill}")
# In a notebook or async code: result = await Runner.run(agent, "Hello!")
result = Runner.run_sync(agent, "Hello!")

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

OpenAI Agents docs

agent_config() hands your agent the skill. With no DecimalAI key it reads your project's files and sends nothing. Needs SDK 0.27 or newer.

Install

pip install "decimalai[openai]"
decimalai skills add marcus-ui-features

Add it to your agent

import json

from openai import OpenAI
from decimalai.openai import agent_config

client = OpenAI()
# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")


def lookup_order(order_id: str) -> str:
    return f"Order {order_id} shipped yesterday."


# Your tools, as Chat Completions takes them, and what answers each.
TOOLS = [{"type": "function", "function": {
    "name": "lookup_order",
    "description": "Look up the status of an order.",
    "parameters": {"type": "object", "properties": {"order_id": {"type": "string"}},
                   "required": ["order_id"]},
}}]
FUNCTIONS = {"lookup_order": lookup_order}

question = "Where is order A1001?"
with support.run(question) as run:  # one user message, one run
    # run.system is your prompt, then the skill list.
    messages = [{"role": "system", "content": run.system}, run.message]
    while True:
        reply = client.chat.completions.create(
            model="gpt-5.4-mini",
            messages=messages,
            tools=[*TOOLS, *run.tools],  # your tools, then load_skill
        ).choices[0].message
        messages.append(reply)
        if not reply.tool_calls:
            break
        for call in reply.tool_calls:
            # load_skill is answered by the run; your own tools by FUNCTIONS.
            function = FUNCTIONS.get(call.function.name)
            messages.append(run.tool_result(call) or {
                "role": "tool", "tool_call_id": call.id,
                "content": function(**json.loads(call.function.arguments)) if function
                else f"There is no tool named {call.function.name!r}.",
            })
print(reply.content)

# The Responses API takes run.response_tools instead of run.tools.

Install

pip install "decimalai[openai]"

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

import json

from openai import OpenAI
from decimalai.openai import agent_config

client = OpenAI()
# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")


def lookup_order(order_id: str) -> str:
    return f"Order {order_id} shipped yesterday."


# Your tools, as Chat Completions takes them, and what answers each.
TOOLS = [{"type": "function", "function": {
    "name": "lookup_order",
    "description": "Look up the status of an order.",
    "parameters": {"type": "object", "properties": {"order_id": {"type": "string"}},
                   "required": ["order_id"]},
}}]
FUNCTIONS = {"lookup_order": lookup_order}

question = "Where is order A1001?"
with support.run(question) as run:  # one user message, one run
    # run.system is your prompt, then the skill list.
    messages = [{"role": "system", "content": run.system}, run.message]
    while True:
        reply = client.chat.completions.create(
            model="gpt-5.4-mini",
            messages=messages,
            tools=[*TOOLS, *run.tools],  # your tools, then load_skill
        ).choices[0].message
        messages.append(reply)
        if not reply.tool_calls:
            break
        for call in reply.tool_calls:
            # load_skill is answered by the run; your own tools by FUNCTIONS.
            function = FUNCTIONS.get(call.function.name)
            messages.append(run.tool_result(call) or {
                "role": "tool", "tool_call_id": call.id,
                "content": function(**json.loads(call.function.arguments)) if function
                else f"There is no tool named {call.function.name!r}.",
            })
print(reply.content)

# The Responses API takes run.response_tools instead of run.tools.

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

from pathlib import Path
from openai import OpenAI

client = OpenAI()
skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
reply = client.chat.completions.create(
    model="gpt-5.4-mini",
    messages=[
        {"role": "system", "content": f"You are a helpful agent.\n\n{skill}"},
        {"role": "user", "content": "Hello!"},
    ],
).choices[0].message

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

OpenAI SDK docs

agent_config() hands your agent the skill. With no DecimalAI key it reads your project's files and sends nothing. Needs SDK 0.27 or newer.

Install

pip install "decimalai[anthropic]"
decimalai skills add marcus-ui-features

Add it to your agent

import anthropic
from decimalai.anthropic import agent_config

client = anthropic.Anthropic()
# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

question = "Hello!"
with support.run(question) as run:  # one user message, one run
    answer = client.beta.messages.tool_runner(
        model="claude-haiku-5-5",
        max_tokens=4096,
        system=run.system,     # your prompt, then the skill list
        tools=[*run.tools],    # your tools, then load_skill
        messages=[{"role": "user", "content": question}],
    ).until_done()

Install

pip install "decimalai[anthropic]"

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

import anthropic
from decimalai.anthropic import agent_config

client = anthropic.Anthropic()
# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

question = "Hello!"
with support.run(question) as run:  # one user message, one run
    answer = client.beta.messages.tool_runner(
        model="claude-haiku-5-5",
        max_tokens=4096,
        system=run.system,     # your prompt, then the skill list
        tools=[*run.tools],    # your tools, then load_skill
        messages=[{"role": "user", "content": question}],
    ).until_done()

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

from pathlib import Path
import anthropic

client = anthropic.Anthropic()
skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
reply = client.messages.create(
    model="claude-haiku-5-5",
    max_tokens=4096,
    system=f"You are a helpful agent.\n\n{skill}",
    messages=[{"role": "user", "content": "Hello!"}],
)

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Anthropic docs

agent_config() hands your agent the skill. With no DecimalAI key it reads your project's files and sends nothing. Needs SDK 0.27 or newer.

Install

pip install "decimalai[google-genai]"
decimalai skills add marcus-ui-features

Add it to your agent

from google import genai
from google.genai import types
from decimalai.google_genai import agent_config

client = genai.Client()
# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")


def lookup_order(order_id: str) -> str:
    return f"Order {order_id} shipped yesterday."


# Your functions, as declarations for the model, and what answers each.
TOOLS = [{"function_declarations": [{
    "name": "lookup_order",
    "description": "Look up the status of an order.",
    "parameters_json_schema": {"type": "object", "properties": {"order_id": {"type": "string"}},
                               "required": ["order_id"]},
}]}]
FUNCTIONS = {"lookup_order": lookup_order}

question = "Where is order A1001?"
with support.run(question) as run:  # one user message, one run
    config = types.GenerateContentConfig(
        system_instruction=run.system,     # your prompt, then the skill list
        tools=[*TOOLS, *run.tool_params],  # your functions, then load_skill
    )
    contents = [{"role": "user", "parts": [{"text": run.message}]}]
    while True:
        response = client.models.generate_content(
            model="gemini-3.5-flash", contents=contents, config=config,
        )
        if not response.function_calls:
            break
        contents.append(response.candidates[0].content)
        parts = []
        for call in response.function_calls:
            # load_skill is answered by the run; your own functions by FUNCTIONS.
            # A loop of your own rather than automatic function calling, which
            # raises KeyError when the model asks for a function you did not pass.
            function = FUNCTIONS.get(call.name)
            parts.append(run.tool_result(call) or {"function_response": {
                "name": call.name, "id": call.id,
                "response": {"result": function(**(call.args or {})) if function
                             else f"There is no function named {call.name!r}."},
            }})
        contents.append({"role": "user", "parts": parts})
print(response.text)

Install

pip install "decimalai[google-genai]"

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

from google import genai
from google.genai import types
from decimalai.google_genai import agent_config

client = genai.Client()
# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")


def lookup_order(order_id: str) -> str:
    return f"Order {order_id} shipped yesterday."


# Your functions, as declarations for the model, and what answers each.
TOOLS = [{"function_declarations": [{
    "name": "lookup_order",
    "description": "Look up the status of an order.",
    "parameters_json_schema": {"type": "object", "properties": {"order_id": {"type": "string"}},
                               "required": ["order_id"]},
}]}]
FUNCTIONS = {"lookup_order": lookup_order}

question = "Where is order A1001?"
with support.run(question) as run:  # one user message, one run
    config = types.GenerateContentConfig(
        system_instruction=run.system,     # your prompt, then the skill list
        tools=[*TOOLS, *run.tool_params],  # your functions, then load_skill
    )
    contents = [{"role": "user", "parts": [{"text": run.message}]}]
    while True:
        response = client.models.generate_content(
            model="gemini-3.5-flash", contents=contents, config=config,
        )
        if not response.function_calls:
            break
        contents.append(response.candidates[0].content)
        parts = []
        for call in response.function_calls:
            # load_skill is answered by the run; your own functions by FUNCTIONS.
            # A loop of your own rather than automatic function calling, which
            # raises KeyError when the model asks for a function you did not pass.
            function = FUNCTIONS.get(call.name)
            parts.append(run.tool_result(call) or {"function_response": {
                "name": call.name, "id": call.id,
                "response": {"result": function(**(call.args or {})) if function
                             else f"There is no function named {call.name!r}."},
            }})
        contents.append({"role": "user", "parts": parts})
print(response.text)

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

from pathlib import Path
from google import genai
from google.genai import types

client = genai.Client()
skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
response = client.models.generate_content(
    model="gemini-3.5-flash",
    contents="Hello!",
    config=types.GenerateContentConfig(system_instruction=f"You are a helpful agent.\n\n{skill}"),
)

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Gemini API docs

agent_config() hands your agent the skill. With no DecimalAI key it reads your project's files and sends nothing. Needs SDK 0.27 or newer.

Install

pip install "decimalai[langchain]" langchain-openai
decimalai skills add marcus-ui-features

Add it to your agent

from langchain.agents import create_agent
from decimalai.langchain import agent_config

# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

agent = create_agent(
    "openai:gpt-5.4-mini",
    tools=[],                         # your tools; the middleware adds load_skill
    middleware=[support.middleware],  # your prompt, the skill list and load_skill
)
result = agent.invoke({"messages": [{"role": "user", "content": "Hello!"}]})

Install

pip install "decimalai[langchain]" langchain-openai

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

from langchain.agents import create_agent
from decimalai.langchain import agent_config

# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

agent = create_agent(
    "openai:gpt-5.4-mini",
    tools=[],                         # your tools; the middleware adds load_skill
    middleware=[support.middleware],  # your prompt, the skill list and load_skill
)
result = agent.invoke({"messages": [{"role": "user", "content": "Hello!"}]})

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

from pathlib import Path
from langchain.agents import create_agent

skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
agent = create_agent("openai:gpt-5.4-mini", tools=[], system_prompt=f"You are a helpful agent.\n\n{skill}")
result = agent.invoke({"messages": [{"role": "user", "content": "Hello!"}]})

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

LangChain docs

CrewAI's own skill loader reads the installed folder. No DecimalAI account needed.

Install

pip install "decimalai>=0.16" "crewai>=1.15.27"
decimalai skills add marcus-ui-features

Add it to your agent

import decimalai.crewai
from crewai import Agent, Crew, Task

agent = Agent(
    role="Support", goal="Help the customer", backstory="A support agent.",
    llm=llm,                               # your own CrewAI LLM
    skills=decimalai.crewai.skills(),      # the installed folder
    tools=decimalai.crewai.skill_tools(),  # reads a skill's files, runs its scripts
)
task = Task(description="Hello!", expected_output="an answer", agent=agent)
Crew(agents=[agent], tasks=[task]).kickoff()

The same install from Python, for a notebook or a setup script. CrewAI's own skill loader reads the installed folder. No DecimalAI account needed.

Install

pip install "decimalai>=0.16" "crewai>=1.15.27"

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

import decimalai.crewai
from crewai import Agent, Crew, Task

agent = Agent(
    role="Support", goal="Help the customer", backstory="A support agent.",
    llm=llm,                               # your own CrewAI LLM
    skills=decimalai.crewai.skills(),      # the installed folder
    tools=decimalai.crewai.skill_tools(),  # reads a skill's files, runs its scripts
)
task = Task(description="Hello!", expected_output="an answer", agent=agent)
Crew(agents=[agent], tasks=[task]).kickoff()

No DecimalAI package. CrewAI's own loader reads the folder, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

from pathlib import Path
from crewai import Agent, Crew, Task

agent = Agent(
    role="Support", goal="Help the customer", backstory="A support agent.",
    llm=llm,                         # your own CrewAI LLM
    skills=[Path(".agents/skills")],
)
task = Task(description="Hello!", expected_output="an answer", agent=agent)
Crew(agents=[agent], tasks=[task]).kickoff()

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

CrewAI docs

agent_config() hands your agent the skill. With no DecimalAI key it reads your project's files and sends nothing. Needs SDK 0.27 or newer.

Install

pip install "decimalai[adk]"
decimalai skills add marcus-ui-features

Add it to your agent

from decimalai.adk import DecimalAIPlugin, agent_config
from google.adk.agents import LlmAgent
from google.adk.apps import App

# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

agent = LlmAgent(
    name="support",          # ADK needs a Python identifier
    model="gemini-3.5-flash",
    instruction=support.instruction,  # your prompt, then the skill list
    tools=[*support.tools],           # your tools, then load_skill
)
# DecimalAIPlugin makes each invocation of runners built from this App one trace.
app = App(name="support", root_agent=agent, plugins=[DecimalAIPlugin()])

Prefer ADK's own loader? SkillToolset(skills=decimalai.adk.skills(), ...) reads the same folder. Use one or the other: a skill delivered both ways reaches the prompt twice.

Install

pip install "decimalai[adk]"

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

from decimalai.adk import DecimalAIPlugin, agent_config
from google.adk.agents import LlmAgent
from google.adk.apps import App

# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

agent = LlmAgent(
    name="support",          # ADK needs a Python identifier
    model="gemini-3.5-flash",
    instruction=support.instruction,  # your prompt, then the skill list
    tools=[*support.tools],           # your tools, then load_skill
)
# DecimalAIPlugin makes each invocation of runners built from this App one trace.
app = App(name="support", root_agent=agent, plugins=[DecimalAIPlugin()])

Prefer ADK's own loader? SkillToolset(skills=decimalai.adk.skills(), ...) reads the same folder. Use one or the other: a skill delivered both ways reaches the prompt twice.

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

from pathlib import Path
from google.adk.agents import LlmAgent

skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
agent = LlmAgent(
    name="support",
    model="gemini-3.5-flash",
    instruction=lambda context: f"You are a helpful agent.\n\n{skill}",
)

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Google ADK docs

agent_config() hands your agent the skill. With no DecimalAI key it reads your project's files and sends nothing. Needs SDK 0.27 or newer.

Install

pip install "decimalai[pydantic-ai]"
decimalai skills add marcus-ui-features

Add it to your agent

from pydantic_ai import Agent
from decimalai.pydantic_ai import agent_config

# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

agent = Agent(
    "openai:gpt-4o-mini",
    name=support.name,
    tools=[],                 # your tools; the capability adds load_skill
    capabilities=[support],   # your prompt, the skill list and load_skill
)
# In a notebook or async code: result = await agent.run("Hello!")
result = agent.run_sync("Hello!")

On the Pydantic AI harness, decimalai.pydantic_ai_harness.skills(project) uses its own loader instead.

Install

pip install "decimalai[pydantic-ai]"

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

from pydantic_ai import Agent
from decimalai.pydantic_ai import agent_config

# With no DECIMAL_API_KEY this reads the skills your project lists, from disk.
support = agent_config("support", fallback="You are a helpful agent.")

agent = Agent(
    "openai:gpt-4o-mini",
    name=support.name,
    tools=[],                 # your tools; the capability adds load_skill
    capabilities=[support],   # your prompt, the skill list and load_skill
)
# In a notebook or async code: result = await agent.run("Hello!")
result = agent.run_sync("Hello!")

On the Pydantic AI harness, decimalai.pydantic_ai_harness.skills(project) uses its own loader instead.

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

from pathlib import Path
from pydantic_ai import Agent

skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
agent = Agent("openai:gpt-4o-mini", instructions=f"You are a helpful agent.\n\n{skill}")
# In a notebook or async code: result = await agent.run("Hello!")
result = agent.run_sync("Hello!")

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Pydantic AI docs

Deep Agents' own skill loader reads the installed folder. No DecimalAI account needed.

Install

pip install "decimalai>=0.16" deepagents
decimalai skills add marcus-ui-features

Add it to your agent

import decimalai.deepagents
from deepagents import create_deep_agent

agent = create_deep_agent(model=model, **decimalai.deepagents.skills())
agent.invoke({"messages": [{"role": "user", "content": "Hello!"}]})

The default backend reads files but has no shell. To run a skill's scripts, pass skills(backend=LocalShellBackend(...)).

The same install from Python, for a notebook or a setup script. Deep Agents' own skill loader reads the installed folder. No DecimalAI account needed.

Install

pip install "decimalai>=0.16" deepagents

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

import decimalai.deepagents
from deepagents import create_deep_agent

agent = create_deep_agent(model=model, **decimalai.deepagents.skills())
agent.invoke({"messages": [{"role": "user", "content": "Hello!"}]})

The default backend reads files but has no shell. To run a skill's scripts, pass skills(backend=LocalShellBackend(...)).

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

from pathlib import Path
from deepagents import create_deep_agent

skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
agent = create_deep_agent(model=model, system_prompt=f"You are a helpful agent.\n\n{skill}")
agent.invoke({"messages": [{"role": "user", "content": "Hello!"}]})

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Deep Agents docs

Its own skill loader reads the installed folder. No DecimalAI account needed.

Install

pip install "decimalai>=0.16" agent-framework
decimalai skills add marcus-ui-features

Add it to your agent

import asyncio

from agent_framework import Agent
from decimalai.agent_framework import skills

agent = Agent(client=client, instructions="You are a helpful agent.", context_providers=[skills()])
asyncio.run(agent.run("Hello!"))

It caches skills by default, so restart the process after decimalai skills update.

The same install from Python, for a notebook or a setup script. Its own skill loader reads the installed folder. No DecimalAI account needed.

Install

pip install "decimalai>=0.16" agent-framework

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

import asyncio

from agent_framework import Agent
from decimalai.agent_framework import skills

agent = Agent(client=client, instructions="You are a helpful agent.", context_providers=[skills()])
asyncio.run(agent.run("Hello!"))

It caches skills by default, so restart the process after decimalai skills update.

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

import asyncio
from pathlib import Path
from agent_framework import Agent

skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
agent = Agent(client=client, instructions=f"You are a helpful agent.\n\n{skill}")
asyncio.run(agent.run("Hello!"))

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Microsoft Agent Framework docs

Strands' own skill loader reads the installed folder. No DecimalAI account needed.

Install

pip install "decimalai>=0.16" strands-agents
decimalai skills add marcus-ui-features

Add it to your agent

from decimalai.strands import skills
from strands import Agent
from strands.vended_tools import file_editor, shell

agent = Agent(
    model=model,                # always pass one: the default is Amazon Bedrock
    system_prompt="You are a helpful agent.",
    tools=[file_editor, shell],
    plugins=[skills()],
)
agent("Hello!")

Strands loads an agent's skills once, so build the agent again after decimalai skills update.

The same install from Python, for a notebook or a setup script. Strands' own skill loader reads the installed folder. No DecimalAI account needed.

Install

pip install "decimalai>=0.16" strands-agents

Add it to your agent

from decimalai import skillpkg

# Writes .agents/skills and .decimal/skills.toml. Safe to run twice.
result = skillpkg.add("marcus-ui-features")
if result.exit_code:
    raise SystemExit(result.problems)

from decimalai.strands import skills
from strands import Agent
from strands.vended_tools import file_editor, shell

agent = Agent(
    model=model,                # always pass one: the default is Amazon Bedrock
    system_prompt="You are a helpful agent.",
    tools=[file_editor, shell],
    plugins=[skills()],
)
agent("Hello!")

Strands loads an agent's skills once, so build the agent again after decimalai skills update.

No DecimalAI package. The whole skill goes in every prompt, and nothing pins or updates it.

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

Give it to your agent

from pathlib import Path
from strands import Agent

skill = Path(".agents/skills/marcus-ui-features/SKILL.md").read_text()
agent = Agent(model=model, system_prompt=f"You are a helpful agent.\n\n{skill}")
agent("Hello!")

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Strands docs

Adds every file the skill has, pinned so you can update it. Cursor, Copilot, Cline and Warp read this folder by themselves.

pip install "decimalai>=0.15"
decimalai skills add marcus-ui-features

No Python or account. Cursor, Copilot, Cline and Warp read this folder by themselves.

Save it into your project

curl -fsSL --create-dirs -o .agents/skills/marcus-ui-features/SKILL.md https://app.decimal.ai/s/marcus-ui-features/SKILL.md

Copy SKILL.md

Save it in your project, as

.agents/skills/marcus-ui-features/SKILL.md

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Cursor and other editors docs

Fetch the file and give its text to your model as instructions. No account or package needed.

Get the file

curl -fsSL https://app.decimal.ai/s/marcus-ui-features/SKILL.md

Read the summary as JSON

curl -fsSL https://app.decimal.ai/s/marcus-ui-features.json

This gets SKILL.md only. The skill's 1 other file is not included.

Other ways to add it

Other setups docs

You don't need a DecimalAI account.

Version: v5, tested 9/2/2026
Source: marcus/sidecar ↗
License: MIT

Manage it in DecimalAI

Saved prompts and skills, pinned versions, and traces of this skill in your runs. DecimalAI does not run your agent.

Claude Code reads files from your project, so DecimalAI config does not apply there.

On Claude Agent SDK: save the skill to an agent here, set DECIMAL_API_KEY, and the same code uses it with no command to run. Changes you save reach the next run with no redeploy.

On OpenAI Agents: save the skill to an agent here, set DECIMAL_API_KEY, and the same code uses it with no command to run. Changes you save reach the next run with no redeploy.

On OpenAI SDK: save the skill to an agent here, set DECIMAL_API_KEY, and the same code uses it with no command to run. Changes you save reach the next run with no redeploy.

On Anthropic: save the skill to an agent here, set DECIMAL_API_KEY, and the same code uses it with no command to run. Changes you save reach the next run with no redeploy.

On Gemini API: save the skill to an agent here, set DECIMAL_API_KEY, and the same code uses it with no command to run. Changes you save reach the next run with no redeploy.

On LangChain: save the skill to an agent here, set DECIMAL_API_KEY, and the same code uses it with no command to run. Changes you save reach the next run with no redeploy.

On CrewAI: set DECIMAL_API_KEY and add decimalai.init(crewai=True) to record runs and skill use. The skill version stays in your repo.

On Google ADK: save the skill to an agent here, set DECIMAL_API_KEY, and the same code uses it with no command to run. Changes you save reach the next run with no redeploy.

On Pydantic AI: save the skill to an agent here, set DECIMAL_API_KEY, and the same code uses it with no command to run. Changes you save reach the next run with no redeploy.

On Deep Agents: set DECIMAL_API_KEY and add decimalai.init(langchain=True) to record runs and skill use. The skill version stays in your repo.

On Microsoft Agent Framework: set DECIMAL_API_KEY and add decimalai.init(otel=True, agent_name="support") to record runs and skill use. The skill version stays in your repo.

On Strands: set DECIMAL_API_KEY and add decimalai.init(otel=True, agent_name="support") to record runs and skill use. The skill version stays in your repo.

Editors read files from your project, so DecimalAI config does not apply there.

Anywhere else: record a use with decimalai.log_skill_activation() inside a trace.

Use this skill

SKILL.md

UI Feature Implementation

Single entry point for sidecar UI work. All new modals must use internal/modal. For complete keyboard shortcut listings, see references/keyboard-shortcuts-reference.md.

Quick Checklist

Modals: use internal/modal, render with ui.OverlayModal, avoid manual hit region math
Pills/chips/tabs: use styles.RenderPillWithStyle; auto-fallback when nerdFontsEnabled is false
Keyboard: Commands + FocusContext + bindings must match; names short; priorities set
Mouse: rebuild hit regions on each render; add general regions first, specific last
Rendering: keep output within View width/height to avoid header/footer overlap. Use contentHeight := height - headerLines - footerLines
Testing: verify keyboard, mouse, hover, scrolling, and footer hints
Plugins must NOT render their own footer -- the app renders a unified footer from Commands()

Modals (internal/modal)

All new modals must use internal/modal. See docs/guides/deprecated/declarative-modal-guide.md for the full API.

Create a modal

m := modal.New("Delete Worktree?",
    modal.WithWidth(58),
    modal.WithVariant(modal.VariantDanger),
    modal.WithPrimaryAction("delete"),
).
    AddSection(modal.Text("Name: " + wt.Name)).
    AddSection(modal.Spacer()).
    AddSection(modal.Buttons(
        modal.Btn(" Delete ", "delete", modal.BtnDanger()),
        modal.Btn(" Cancel ", "cancel"),
    ))

Render in View

func (p *Plugin) renderDeleteView(width, height int) string {
    background := p.renderListView(width, height)
    rendered := p.deleteModal.Render(width, height, p.mouseHandler)
    return ui.OverlayModal(background, rendered, width, height)
}

Handle input in Update

case tea.KeyMsg:
    action, cmd := p.deleteModal.HandleKey(msg)
    if action != "" {
        return p.handleModalAction(action)
    }
    return p, cmd

case tea.MouseMsg:
    action := p.deleteModal.HandleMouse(msg, p.mouseHandler)
    if action != "" {
        return p.handleModalAction(action)
    }
    return p, nil

Modal initialization and caching (critical)

Always call ensureModal() in BOTH View and Update handlers. Create an ensure function that:

Returns early if required state is missing
Caches based on width to avoid rebuilding every frame
Creates the modal only when needed

func (p *Plugin) ensureMyModal() {
    if p.targetItem == nil {
        return
    }
    modalW := 50
    if modalW > p.width-4 { modalW = p.width - 4 }
    if modalW < 20 { modalW = 20 }
    if p.myModal != nil && p.myModalWidthCache == modalW {
        return
    }
    p.myModalWidthCache = modalW
    p.myModal = modal.New("Title", modal.WithWidth(modalW), ...).
        AddSection(...)
}

The key handler MUST call ensure before checking nil:

func (p *Plugin) handleMyModalKeys(msg tea.KeyMsg) tea.Cmd {
    p.ensureMyModal()  // CRITICAL: Initialize before nil check
    if p.myModal == nil { return nil }
    action, cmd := p.myModal.HandleKey(msg)
    return cmd
}

Async content invalidation

When modal content depends on async data, invalidate the cache when data arrives:

case MyDataLoadedMsg:
    p.myData = msg.Data
    p.clearMyModal()  // Force rebuild with new content
    return p, nil

Modal keyboard shortcuts and footer hints

Modals need their own focus context and commands for footer hints:

Return a dedicated context from FocusContext()
Add commands for the modal context in Commands()
Add bindings in internal/keymap/bindings.go
Intercept custom keys before modal.HandleKey (Tab/Enter/Esc are handled internally)

func (p *Plugin) FocusContext() string {
    switch p.viewMode {
    case ViewModeError:  return "git-error"
    case ViewModePushMenu: return "git-push-menu"
    default: return "git-status"
    }
}

Modal notes

HandleKey/HandleMouse handle Tab, Shift+Tab, Enter, Esc internally
Backdrop clicks return "cancel"; use WithCloseOnBackdropClick(false) to disable
Use built-in sections (Text, Input, Textarea, Buttons, Checkbox, List, When) before custom layouts
For bespoke layouts, use modal.Custom and return explicit focusable offsets
SetFocus(id) auto-scrolls viewport to focused element
Prefer ui.OverlayModal(background, modal, width, height) for dimmed overlays; do not pre-center with lipgloss.Place

Background colors (critical)

Lipgloss Background() does not cascade into child content. ANSI resets clear the parent background. Solution: replace ANSI resets within viewport lines with reset + background re-apply, then pad short lines. See fillBackground in internal/modal/layout.go.

Pill-Shaped Elements (internal/styles)

Controlled by nerdFontsEnabled in ~/.config/sidecar/config.json (ui.nerdFontsEnabled).

// With explicit colors
label := styles.RenderPill("Output", styles.TextPrimary, styles.Primary, "")

// With a lipgloss.Style (preferred for tabs/chips)
active := styles.RenderPillWithStyle("Output", styles.BarChipActive, "")
inactive := styles.RenderPillWithStyle("Diff", styles.BarChip, "")

Available styles: styles.BarChip (inactive), styles.BarChipActive (active), or custom lipgloss.Style.

Test with both nerdFontsEnabled: true and false to verify fallback.

Keyboard Shortcuts

For complete per-plugin shortcut listings, see references/keyboard-shortcuts-reference.md.

Three things must match

Command ID in Commands() (e.g., "stage-file")
Binding command in internal/keymap/bindings.go (e.g., "stage-file")
Context string in both places (e.g., "git-status")

// 1) Commands()
{ID: "stage-file", Name: "Stage", Context: "git-status", Priority: 1}

// 2) FocusContext()
func (p *Plugin) FocusContext() string { return "git-status" }

// 3) bindings.go
{Key: "s", Command: "stage-file", Context: "git-status"}

Multiple contexts (view modes)

Return different context strings from FocusContext() for different modes. Each context gets its own footer hints and key bindings.

Priority guidelines

1: Primary actions (Stage, Commit, Open)
2: Secondary actions (Diff, Search, Push)
3: Tertiary actions (History, Refresh)
4+: Palette only

Root contexts (q behavior)

In root contexts, q shows quit confirmation. In non-root, q navigates back. Root contexts: global, conversations, conversations-sidebar, git-status, git-status-commits, git-status-diff, file-browser-tree, workspace-list, td-monitor.

Update isRootContext() in internal/app/update.go when adding new contexts.

Text input contexts

When a view has text input, implement plugin.TextInputConsumer and return true while active. This prevents app-level shortcuts from intercepting typed characters.

func (p *Plugin) ConsumesTextInput() bool {
    return p.showMyModal
}

Footer rendering flow

footerHints()
    +-- pluginFooterHints() -> Commands() filtered by FocusContext(), sorted by Priority
    +-- globalFooterHints() -> App-level hints
renderHintLineTruncated(hints, availableWidth)
    -> Renders left-to-right until width exceeded

Keyboard checklist

Command in Commands() with ID, Name, Context, Priority
FocusContext() returns matching context
Binding in internal/keymap/bindings.go
Key handled in Update() if app does not intercept
No conflicting keys in same context
Short footer hint names, primary actions Priority 1-2
Verify q behavior with isRootContext()

Core files

File	Purpose
`internal/plugin/plugin.go`	Command struct, Commands(), FocusContext(), TextInputConsumer
`internal/keymap/bindings.go`	Default key-to-command mappings
`internal/keymap/registry.go`	Runtime binding lookup
`internal/app/update.go`	Key routing, isRootContext()
`internal/app/view.go`	Footer rendering

Scrollbar (internal/ui)

rendered, geom := ui.RenderScrollbarWithState(ui.ScrollbarParams{
    TotalItems:   len(items),
    ScrollOffset: p.scrollOffset,
    VisibleItems: visibleCount,
    TrackHeight:  height,
}, style) // ui.ScrollbarStyle{Thumb: state, Track: state}; zero value renders byte-identically to RenderScrollbar

Every scrollbar backed by real scroll state is interactive under the mouse (macOS-style), including the terminal panes' bars over captured scrollback. Terminal surfaces map presses and drags through tty.WindowScrollbarFor onto the shared window model: the gesture freezes the window at an absolute start, release thaws (offset zero follows again), and history loads defer to release so a mid-gesture renumber cannot shift the mapping. Adoption ledger: docs/plans/active/mouse-draggable-scrollbars.md ("Adoption outcome").

Pattern: reduce content width by 1, render content, render scrollbar, join horizontally with lipgloss.JoinHorizontal(lipgloss.Top, content, scrollbar).

For multi-line items, set TrackHeight to actual terminal rows: visibleCount * linesPerItem.

Mouse contract per surface:

Register ui.RegionScrollbarTrack, then ui.RegionScrollbarThumb, after content regions in the same render pass that builds the HitMap (reverse scan gives the bar its column). Register nothing when geom.HasThumb is false — that column is a spacer.
Thumb press = grab at that row; track press = jump-to-spot anchored at the grabbed row; both end in StartDrag so releasing anywhere settles cleanly. Drag maps through ui.OffsetAtRow against the press-time params snapshot; past-end clamps never end the gesture.
A rapid second press arrives as ActionDoubleClick: answer it like ActionClick (re-grab), never swallow it.
Emphasis derives via ui.HandleStateFrom(hovering, dragging) — intensity modulation on the existing theme keys, no new keys.

Wheel boundaries (required for every new scrollable surface)

Trackpad and Magic Mouse flicks emit hundreds of inertial wheel events. Bubble Tea repaints all of Sidecar after every accepted one, so clamping an offset during Update is too late — the freeze happens before the clamp helps. tea.WithFilter(app.FilterInput) asks one read-only question before Update and View:

Would this exact wheel event change the surface currently under the pointer?

Rule: every new scrollable surface or modal must provide exact pre-update bounds, or explicitly declare why its answer is unknown. "Unknown" is a valid, safe answer — guessing is not. Return true only when the event is a certain no-op.

How to comply:

Implement plugin.WheelBoundaryConsumer on the plugin (WheelAtBoundary(tea.MouseWheelMsg) bool) and add var _ plugin.WheelBoundaryConsumer = (*Plugin)(nil).
Mirror handleMouseScroll's routing exactly — same hit map, same modal precedence — but load nothing, move nothing, render nothing.
Derive the maximum from the same helper the renderer clamps with (internal/scroll.Bounds), never a second copy of the arithmetic.
Declarative modals answer for themselves via modal.WheelAtBoundary(msg, handler); the host only owns precedence between a modal, a nested overlay, and a custom scrolling child. Call Invalidate() when content or geometry changes so a stale layout answers unknown instead of wrong.
Return false (unknown) for: embedded models you do not own, tmux panes with mouse reporting, scrollback with unloaded history, lazy lists that can load more, and anything before its first trustworthy render.
Declare the surface's policy in assembly.WheelBoundaryRegistry (covered / externally-owned / deprecated-exclusion). A new plugin without a row fails the assembly tests; a new ModalKind without a row fails TestEveryModalKindHasALedgerRow in internal/app.
Prove it with the shared stress fixture internal/scroll/scrolltest: scrolltest.Run(t, scrolltest.Tail{...}) feeds hundreds of same-direction events and one reverse event, with no sleeps.

Background: docs/plans/active/scroll-inertia-complete-coverage.md.

Wheel burst coalescing (required for every new scrollable surface)

Boundary drop alone is half the protection. A flick that never reaches a boundary — mid-range inertia over a long card — still delivers one event per notch, and each accepted one is an Update + View repaint. tty.WheelBurst / tty.WheelBursts (internal/tty/wheel.go) coalesce a flick into whole flushes: "how much of this burst has the surface earned" lives in that one place, so a flick travels the same distance on every surface.

Rule: every new scrollable content area applies wheel deltas through the shared burst guard and drops at boundaries — both, not either.

How to comply:

Hold one tty.WheelBurst per scroll surface. A host with one surface embeds the value in whatever struct owns it (internal/overview/preview.go, workspace issuePane); a host with several uses tty.WheelBursts keyed per leaf/region (Files tree + preview, app content deck).
Apply through Add(delta, now); when ok is false the event was held, change nothing, and return early. The held delta rides the next flush — never apply delta directly.
Inject the clock for tests: a wheelNow func() time.Time field (Files), the plugin clock (p.now()), or a Model hook (notificationCentreNow). Tests drive a whole flick without sleeping — see internal/plugins/filebrowser/scroll_burst_test.go and the issue-viewer equivalents beside each host.
Reset the burst wherever the boundary answer is true, so inertia dropped at the top or bottom cannot spend itself into the next gesture. Crossing surfaces with WheelBursts.For resets automatically.
Keyboard scrolling does not coalesce; do not route keys through the burst.

Reference adoptions: embedded terminals (internal/tty/tty.go), Files tree and preview (internal/plugins/filebrowser), workspace terminal + issue panes, overview terminal + issue preview, app content deck + notification centre + issue preview modal.

Mouse Support

Setup

type Plugin struct {
    mouseHandler *mouse.Handler
}
func New() *Plugin {
    return &Plugin{mouseHandler: mouse.NewHandler()}
}

Register hit regions during render

func (p *Plugin) View(width, height int) string {
    p.mouseHandler.Clear()
    p.mouseHandler.HitMap.AddRect("pane", 0, 0, width, height, nil)
    p.mouseHandler.HitMap.AddRect("item", 2, 5, width-4, 1, 0)
    return content
}

Region ordering (critical)

Regions tested in reverse order. Add general regions first, specific regions last.

Pane header controls (internal/ui + internal/panereposition)

A pane header's right edge carries two controls: the layout button ⊞ (U+229E) and the close ×. Both are drawn through ui.ResolveButtonStyle with the same one-cell padding, so a pane header never invents a third button look, and both are gated on the pane_move feature for the layout button's half.

Reserve, do not measure. ui.ReserveHeaderControls(width, controls ...HeaderControl) returns the tab strip's usable width and each control's column in one call; panereposition.ReserveMovableHeader(width, movable, hasClose) is the pane-side wrapper. Each host binds it once per frame in its own reserveHeader/composeHeader pair (workspace.Plugin, overview.Model, app.appContentDeck) so its header renderer, its tab strips and its region sink all measure from one answer — a strip laid out for a different reserve than the header composes is how a tab click lands on the wrong tab.

movable comes from the tree, via panereposition.Movable: it is false with no tree and false for a tree of one leaf. PlanMove refuses every destination on a single leaf, so a control there is a target the user aims at for nothing, and a header with no leaf at all used to compare hover against leaf 0 — which every un-hovered header matches — and paint a permanently hovered button. ui.ReserveHeaderClose remains a one-line compatibility wrapper for headers that carry only the ×. The arithmetic assumes a one-column glyph and the test suite pins ansi.StringWidth of the rendered label; a wider glyph silently shifts every hit region on the row.

Drop order as the row narrows: the layout button goes first, the close × last. A control is dropped all-or-nothing. A half-drawn control is a target whose meaning cannot be recovered, and the close button is the one a user cannot work around.

The Layout region rung is after Title and before Close. paneframe.RegionSink registers Layout(node *panelayout.Node, hit Box) at that rung for the same reason RegisterRegions documents for the close button, one step earlier: regions are tested in reverse order, so the later-registered Close wins the cell it actually occupies while Layout still outranks the title strip underneath it. All three pane hosts implement it beside their close-region binding, with the same hover tracking.

The button opens panereposition.Controller — the same modal M opens. See .claude/skills/keyboard-shortcuts/SKILL.md for the key and its target resolution, and .claude/skills/drag-pane/SKILL.md for where the region sits in the windowing model.

Coordinate system

App offsets Y by headerHeight (the single painted header row) before forwarding to plugins. Plugins operate in local coords where Y=0 is plugin content top.

Common patterns

Click to select/focus, scroll wheel to move, double-click to open
Drag regions for pane resizing
Hover for visual feedback (focus takes precedence)

Mouse troubleshooting

Symptom	Fix
Clicks don't register	Check region order (pane first)
Y offsets wrong	Account for borders, padding, headers
Scroll over items broken	Include item regions in scroll routing
Double-click fails	Ensure consistent region ID/bounds
Drag broken	Call StartDrag on click, check DragRegion during drag

When it activates

Automatically, when a task matches. Use when implementing UI features, handling user input, adding keyboard shortcuts, building modals, or working on UX improvements.

About this skill

Automatic

Frontend / UI pack

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v5 — 9/2/2026

View 15 scanner checks

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review

Source

Imported

marcus / sidecar

.claude/skills/ui-features/SKILL.md

View on GitHub ↗

License MITImported 9/2/2026Version v5Bundled 1 file

Illustrative Want to see what marcus/ui-features would put in front of your model? Preview the rendered body and check its trigger phrases — no LLM call, no signup.

Related skills

Skills that do similar work, with their headline benchmark lift.

From the same source and nearby in the catalogue.

Ready to supercharge your AI agents?

SkillScore

Safety

What it changes

Track record

Use this skill

UI Feature Implementation

Quick Checklist

Modals (internal/modal)

Create a modal

Render in View

Handle input in Update

Modal initialization and caching (critical)

Async content invalidation

Modal keyboard shortcuts and footer hints

Modal notes

Background colors (critical)

Pill-Shaped Elements (internal/styles)

Keyboard Shortcuts

Three things must match

Multiple contexts (view modes)

Priority guidelines

Root contexts (q behavior)

Text input contexts

Footer rendering flow

Keyboard checklist

Core files

Scrollbar (internal/ui)

Wheel boundaries (required for every new scrollable surface)

Wheel burst coalescing (required for every new scrollable surface)

Mouse Support

Setup

Register hit regions during render

Region ordering (critical)

Pane header controls (internal/ui + internal/panereposition)

Coordinate system

Common patterns

Mouse troubleshooting

When it activates

SkillSafety

Source

Related skills

More in the registry