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Write Milestone Brief · gsd-build | DecimalAI

productivityby gsd-build

Write Milestone Brief

gsd-build/write-milestone-brief

Source gsd-build/gsd-2 ↗License MIT

Synthesize the current conversation into a milestone brief (PRD). Writes to `M###-CONTEXT.md` by default, or files a GitHub issue only with explicit user confirmation.

NewMaintained

Automatic

Product Management pack

Last verified 9/27/2026

What it changes

1 of 22 test cases passed with the skill.

Pass-rate lift: —
Tokens: +55%
Agent turns: 0%
Response time: -18%

Model gemini-3.6-flashMeasured 9/27/2026v11 of 22 cases passed with skill · 1 comparable

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

Lift withheld: 1 comparable cases; this report requires 8.

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/gsd-build-write-milestone-brief/SKILL.md https://app.decimal.ai/s/gsd-build-write-milestone-brief/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add gsd-build-write-milestone-brief, 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/gsd-build-write-milestone-brief/ and pins it in .decimal/skills.lock

decimalai skills add gsd-build-write-milestone-brief

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

curl -fsSL --create-dirs -o .claude/skills/gsd-build-write-milestone-brief/SKILL.md https://app.decimal.ai/s/gsd-build-write-milestone-brief/SKILL.md

Raw file: /s/gsd-build-write-milestone-brief/SKILL.md ↗ · machine-readable summary at /s/gsd-build-write-milestone-brief.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

See it in action

A test case the skill fixed. Same model, same prompt, with and without the skill.

Prompt

We just finished drafting the context brief for milestone M011 (Data Export). I feel our data retention and purge strategy might still be weak. What next steps should be offered to address this uncertainty?

What was checked, without and with the skill
Checked	Without skill	With skill
Iterating on the brief using grill-me is offered as an available next step.	Missed	Passed

case-16 · gemini-3.6-flash · 9/27/2026 · answers are capped and redacted

What's inside

The instructions your model reads when the skill loads.

SKILL.md130 linessingle file

Typical invocation points:

User says "capture this" or "write it up" after a planning discussion
End of a discuss phase before moving to plan
User wants to hand the work off to another agent or a human teammate

<core_principle> SYNTHESIZE, DO NOT RE-INTERVIEW. Use what is already in this conversation. If a decision is genuinely missing, note it in Open Questions — do not relitigate.

REAL OUTCOMES, NOT TASKS. M###-CONTEXT.md describes what the user can do when the milestone ships, what scenarios must pass for "done," and what architectural decisions were made. It does NOT list tasks or implementation steps — those belong in M###-ROADMAP.md and S##-PLAN.md.

NO FILE PATHS OR LINE NUMBERS IN THE BRIEF. Those go stale. Describe modules, interfaces, and behaviors. The roadmap and plans can cite code locations; the brief should outlive refactors. </core_principle>

Step 1: Locate the target

Find the active milestone:

Read .gsd/STATE.md — it names the active milestone.
If no milestone is active, ask the user whether this is a new milestone (create directory + files) or appending to an existing one.
For a new milestone, use gsd_milestone_new or the /gsd new-milestone flow — do not create directories by hand.

Step 2: Read the template

Read src/resources/extensions/gsd/templates/context.md (the full path is shown in the templatesDir system-prompt field). Match its structure exactly — parsers and downstream prompts depend on the headings.

Step 3: Sketch the modules

Before filling the template, sketch the major modules the milestone will build or modify. Actively look for opportunities to extract deep modules — ones that encapsulate a lot of functionality in a simple, testable interface that rarely changes. A deep module is more testable, more AI-navigable, and survives refactors.

If the modules are non-obvious, offer the user a brief check-in: "The milestone touches modules A, B, and C. A can be extracted as a deep module that hides X. Does that match your thinking?" One round. Then proceed.

Track record

Benchmark

1 / 22

test cases passed with the skill

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 v5 — 8/31/2026

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

gsd-build / gsd-2

src/resources/skills/write-milestone-brief/SKILL.md

View on GitHub ↗

License MITImported 8/31/2026Version v1

Other skills for the same job

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

open-gsd/write-milestone-briefSynthesize the current conversation into a milestone brief (PRD). Writes to `M###-CONTEXT.md` by default, or files a GitHub issue only with explicit user confirmation. Use when asked to "turn this into a PRD", "draft a milestone brief", "capture this context", "write it up", or when enough has been discussed to commit the plan to paper. Does not interview — it synthesizes what is already known.Near-identical description+5 pp pass-rate lift

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