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GitHub Custom Agent File Format · majiayu000 | DecimalAI

agent toolingby majiayu000

GitHub Custom Agent File Format

majiayu000/custom-agents

Source majiayu000/claude-skill-registry ↗License MIT

This document describes the GitHub custom agent file format used by GitHub Copilot to provide repository-specific or task-specific instructions to AI coding agents.

SkillScore100Maintained

Automatic

AI Engineer pack

Last verified 8/19/2026

What it changes

Passed 22 of 22 test cases with the skill, and 12 of 22 without it.

Without skill55%

With skill100%

Checks it passed that the model alone missed

The tools list includes pr.
The tools list includes read.
The tools list includes editFiles.

and 12 more in the full report

10 fixed12 passed either way0 still failing0 broke

Pass-rate lift: +45 pp
Tokens: +222%
Agent turns: 0%
Response time: -40%

Model gemini-3.6-flashMeasured 8/19/2026v222 of 22 cases passed with skill

Tokens, turns and time describe resource use, not a dollar price.

Use this skill

Save it into your project's skills folder. Claude Code picks it up in its next session.

curl -fsSL --create-dirs -o .claude/skills/majiayu000-custom-agents/SKILL.md https://app.decimal.ai/s/majiayu000-custom-agents/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add majiayu000-custom-agents, and start Claude Code with claude --plugin-dir "$(git rev-parse --show-toplevel)/.agents"

1 · One-time — install the CLI (docs ↗)

pip install "decimalai>=0.15"

2 · Get the skill — writes .agents/skills/majiayu000-custom-agents/ and pins it in .decimal/skills.lock

decimalai skills add majiayu000-custom-agents

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/majiayu000-custom-agents/SKILL.md https://app.decimal.ai/s/majiayu000-custom-agents/SKILL.md

Raw file: /s/majiayu000-custom-agents/SKILL.md ↗ · machine-readable summary at /s/majiayu000-custom-agents.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

See it in action

One of 10 test cases the skill fixed. Same model, same prompt, with and without the skill.

1 of 10

Prompt

Explain the import restriction when referencing custom agent files in a GitHub Agentic Workflow markdown document, and show a valid YAML frontmatter example.

What was checked, without and with the skill
Checked	Without skill	With skill
The response explicitly mentions that only one custom agent file is permitted per workflow.	Missed	Passed
The example frontmatter uses imports referencing a single agent file.	Missed	Passed

case-19 · gemini-3.6-flash · 8/19/2026 · answers are capped and redacted

What's inside

The instructions your model reads when the skill loads.

SKILL.md567 linessingle file

GitHub Custom Agent File Format

This document describes the GitHub custom agent file format used by GitHub Copilot to provide repository-specific or task-specific instructions to AI coding agents.

Overview

GitHub Copilot supports custom agent instructions through Markdown files with YAML frontmatter. These files allow you to define specialized agent behaviors, tool access, and custom workflows that tailor Copilot's behavior to your repository's needs.

File Locations

Custom agent files can be placed in several locations, each serving a different scope:

1. Repository-wide Instructions

File: .github/copilot-instructions.md
Scope: Applies to all code generation in the repository
Use case: General coding standards, security requirements, testing practices

2. Path-specific Instructions

Directory: .github/instructions/
Pattern: *.instructions.md (e.g., frontend.instructions.md, backend.instructions.md)
Scope: Can target specific directories or file patterns using applyTo in frontmatter
Use case: Framework-specific guidelines, component-specific rules

3. Custom Agent Profiles

Directory: .github/agents/ or .github/copilot/instructions/
Pattern: AGENTS.md, *.md (e.g., readme-creator.md, test-writer.md)
Scope: Defines specialized agents with specific capabilities and instructions
Use case: Task-specific agents (documentation, testing, refactoring)

4. agentic workflow integration

Location: Imported via imports field in workflow frontmatter
Pattern: Any markdown files under .github/agents/ directory
Scope: Custom agent for specific agentic workflow execution
Use case: Workflow-specific agent configuration
Important: Only one agent file is allowed per workflow

File Format

Basic Structure

Track record

Benchmark

22 / 22

test cases passed, vs 12 / 22 without

Adoption

Users: 0
Times used: 0

Safety and source details

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v4 — 8/3/2026

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

majiayu000 / claude-skill-registry

skills/agent/custom-agents-github-gh-aw/SKILL.md

View on GitHub ↗

License MITImported 8/3/2026Version v2

Other skills for the same job

Published skills whose descriptions closely match this one, with their headline benchmark lift.

github/custom-agentsDefine and validate GitHub custom agent files, prompts, and examples.Close match+57 pp pass-rate lift

More skills from the same source and nearby in the registry, with their headline benchmark lift.

Ready to supercharge your AI agents?

See it in action

What's inside

GitHub Custom Agent File Format

Overview

File Locations

1. Repository-wide Instructions

2. Path-specific Instructions

3. Custom Agent Profiles

4. agentic workflow integration

File Format

Basic Structure

Track record

Benchmark

Adoption

SkillSafety

Source

Other skills for the same job

Related skills