Borrowing it
Nothing to install: this file belongs to moberghr/mtk-agent-toolkit. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/moberghr/mtk-agent-toolkit/main/.claude/skills/prior-work-check/SKILL.mdgit clone --depth 1 https://github.com/moberghr/mtk-agent-toolkitWrote 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/skills/moberghr/mtk-agent-toolkit/prior-work-check)<a href="https://agentmods.dev/skills/moberghr/mtk-agent-toolkit/prior-work-check"><img src="https://agentmods.dev/badge/skills/moberghr/mtk-agent-toolkit/prior-work-check/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/skills/moberghr/mtk-agent-toolkit/prior-work-check"><img src="https://agentmods.dev/badge/skills/moberghr/mtk-agent-toolkit/prior-work-check.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Agent Snooping · line 187 Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
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 | $0.00031 | $0.01275 |
| Opus 5.5 | $0.00012 | $0.00510 |
| Sonnet 5.5 | $0.00006 | $0.00255 |
| Haiku 4.5 | $0.00003 | $0.00128 |
Grade A, and why
prior-work-check 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 16d 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.
How it starts
The opening of the file, as written. The whole thing — 107 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Prior Work Check
Tool discipline: read-only —
Read/Grep/Globand read-onlyBashqueries. NeverEdit/Write; report what exists and let the caller decide.
Overview
Before writing new code, confirm the codebase doesn't already do this — re-implementing a capability that exists under a different name is the most common waste in mature codebases. Runs once per implement run: spec-driven step 9 for a fresh request, or Phase 0.7's reconciliation mode when the engineer supplied the plan. Lessons and security-impact classification are covered elsewhere (the lessons query in Phase 0, the spec's security-impact step and drift check) and are not repeated here.
When To Use
spec-driven-developmentstep 9, before the implement Phase 2.5 approval gateimplementPhase 0.7 when a pre-written plan is supplied as input — the reconciliation mode below, so already-implemented batches are not re-run- When the engineer says "let's add an X" and X sounds generic (cache, retry, validator, formatter, normalizer)
When NOT To Use
- Typo fixes, single-line config tweaks, or bug fixes where the file in scope is already named
- A second time in the same run — planning does not re-run it
Workflow
Query — search_prior_work
Look for an existing implementation of the capability under any name.
- Extract 2-4 capability keywords from the spec
summaryandsuccess_criteria. Verbs + nouns ("issue token", "retry policy", "currency formatter"). - Run, in parallel:
grep -rn -i "<keyword>" --include="*.cs" --include="*.py" --include="*.ts" --include="*.tsx" --include="*.js" src/(or the active stack's source roots — read.claude/tech-stack).- If
CODE_INDEX.mdexists at the repo root, query it withbash scripts/query-code-index.sh find "<keyword>"(case-insensitive row search that prints each match prefixed with its## <Domain>section) rather than a rawgrep. If the script is absent (repo bootstrapped before v7.17) or the keyword may live outside table rows (domain headings, prose), fall back togrep -i "<keyword>" CODE_INDEX.md. - If an MCP code-index tool is available (e.g.
mcp__ast-index__*), prefer it over raw grep.
- For each hit, report:
- file:line
- one-line summary of what it does
- whether it can be reused, extended, or is genuinely different
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.
- 16d ago Changed · -92 lines · -2 tokens per session 07b991593f75
- 1mo ago Changed · -12 lines c7d7775faf16
- 2mo ago First seen · 211 lines · 33 tokens per session scan A 7e55d171a3ba
prior-work-check is a skill published in the GitHub repository moberghr/mtk-agent-toolkit (9 stars, last pushed 8d ago), licensed MIT. It adds 31 tokens to every session and 1,275 once invoked, about $0.0001 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 2026-08-31.
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