plan-activate

A command that enables code changes only after a selected development plan has been read and structurally checked.

In plain words
What is it for?
Use it before editing implementation files in projects that require an approved plan and validation record.
Why use it?
It helps prevent implementation from starting with an incomplete or invalid plan. It also warns when the plan has not had an adversarial review.

Command

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add commands/milindgaharwar/fettle/plan-activate
Clone the repo
git clone --depth 1 https://github.com/MilindGaharwar/fettle
Per session 14 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 580 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 98% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00014 $0.00580
Opus 5 $0.00007 $0.00290
Sonnet 5 $0.00003 $0.00116
Haiku 4.5 $0.00001 $0.00058

Measured 2d ago against content hash 43419f5fa5e4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

plan-activate scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

98% identical to fettle-plan-activate — 4 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

commands/plan-activate.md · 62 lines

How it starts

The opening of the file, as written. The whole thing — 62 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/fettle:plan-activate

Activate a development plan to unlock implementation file edits.

Steps

  1. Ask the user which plan file to activate. If they provide a path, use it. If not, search for .md files in docs/plans/ and present the list.

  2. Read the plan file completely.

  3. Run the structural validator:

    python3 -m fettle.plan_validator <PLAN_PATH>
    

    If it fails, report every error verbatim and do NOT activate. The errors name the exact WP and missing method type. Fix the plan first.

  4. Check for adversarial review:

    • Look for a ## Council Review or ## Adversarial Review section in the plan, OR
    • Check if a council report file is referenced in the plan header (e.g., council_report: /path/to/report.md)
    • If neither exists: WARN the user that no adversarial review is on record. For plans with implementation tasks, recommend an adversarial review pass (a second model or a colleague red-teaming the plan) before activation. Strongly recommended but does not hard-block.
  5. If validation passes, write the marker file:

    echo '{"plan": "<PLAN_PATH>", "approved": true, "ts": <UNIX_TIMESTAMP>}' > .fettle/state/active-plan.json
    
  6. Confirm activation:

    Plan activated: <plan name>
    Path: <plan path>
    Work packages: <count>
    Implementation file edits are now allowed.
    

Validation rules enforced (plan_validator.py)

Every WP containing at least one implementation method task (TDD, BUILD, FIX, REFACTOR, CODE, INTEGRATION) must also contain:

Required method What it checks
TDD Unit tests written before implementation
INTEGRATION End-to-end test against the running system
REGRESSION Named failure scenario (must cite incident/bug -- generic "regression test" is blocked)
LIVE Exact command + observable outcome (must include an actual command -- "verify it works" is blocked)

WPs containing only INSPECT, VERIFY, REVIEW, or PROPERTY tasks are exempt.

Read the full file on GitHub · 62 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 62 lines · 14 tokens per session scan A 43419f5fa5e4

Subscribe to this mod's changes

plan-activate is a command published in the GitHub repository MilindGaharwar/fettle (2 stars, last pushed 3d ago), licensed Apache-2.0. It adds 14 tokens to every session and 580 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 98% identical to fettle-plan-activate, differing in 4 lines, and is treated as a copy.