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.
git clone --depth 1 https://github.com/FeatureFactory-io/mimirWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/rules/featurefactory-io/mimir/do-plan-before-doing)<a href="https://agentmods.dev/rules/featurefactory-io/mimir/do-plan-before-doing"><img src="https://agentmods.dev/badge/rules/featurefactory-io/mimir/do-plan-before-doing/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/rules/featurefactory-io/mimir/do-plan-before-doing"><img src="https://agentmods.dev/badge/rules/featurefactory-io/mimir/do-plan-before-doing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00372 | $0.00372 |
| Opus 5.5 | $0.00149 | $0.00149 |
| Sonnet 5.5 | $0.00074 | $0.00074 |
| Haiku 4.5 | $0.00037 | $0.00037 |
Grade A, and why
do-plan-before-doing 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 18d 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.
What it actually says
Rule: Plan Before Doing
Use this rule before any activity that will mutate code, playbook state, project artifacts, tickets, infrastructure, or an external system.
Procedure
- Read the activity guidance, required inputs, linked artifacts/rules, and relevant architecture/specification material in full. Inspect implementation bodies and live state; do not infer completeness from names, signatures, or generated files.
- Validate prerequisites and identify unknowns, human gates, side effects, rollback/retry behavior, and the evidence required for Done.
- If the ADE provides an enforced Plan mode, enter it. Otherwise create or update the activity's explicit execution plan in the location named by its guidance.
- The plan must name ordered steps, dependencies, read/write footprints, safe parallel groups, convergence checks, tests/validation, and approval points.
- Show the plan and obtain required human approval before mutation. Approval of a parent plan covers only side effects explicitly listed there.
- Execute against the approved plan. Update status and evidence after material steps; when reality invalidates an assumption, pause affected work, revise the plan, and renew approval where scope or side effects change.
- Do not invent ADE capabilities. If enforced planning, subagents, or background tasks are unavailable, preserve the same plan/dependency/convergence semantics serially.
Bounded exceptions
- Read-only inspection may precede the plan when needed to make it accurate.
- A deterministic scheduled AIN run may execute from the already approved Charter and Huginn Assessment Contract without new approval per run; changing the contract, variables, thresholds, gating, ticket target, or schedule still requires planning and approval.
- Trivial status reads and idempotent retries that use the same approved inputs and side-effect key do not require a new plan.
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.
- 18d ago Changed · +9 lines · +372 tokens per session 5ff27d29edf9
- 1mo ago First seen · 15 lines · 0 tokens per session scan A be80961c1b04
do-plan-before-doing is a cursor rule published in the GitHub repository FeatureFactory-io/mimir (16 stars, last pushed 17d ago), licensed Apache-2.0. It adds 372 tokens to every session, about $0.0015 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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