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.
npx skills add gabrielmoreira/agent-skills-mirror --skill setup-codebase-harnessgit clone --depth 1 https://github.com/gabrielmoreira/agent-skills-mirrorWrote 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/gabrielmoreira/agent-skills-mirror/setup-codebase-harness)<a href="https://agentmods.dev/skills/gabrielmoreira/agent-skills-mirror/setup-codebase-harness"><img src="https://agentmods.dev/badge/skills/gabrielmoreira/agent-skills-mirror/setup-codebase-harness/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/gabrielmoreira/agent-skills-mirror/setup-codebase-harness"><img src="https://agentmods.dev/badge/skills/gabrielmoreira/agent-skills-mirror/setup-codebase-harness.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 | $0.00103 | $0.01438 |
| Opus 5 | $0.00051 | $0.00719 |
| Sonnet 5 | $0.00021 | $0.00288 |
| Haiku 4.5 | $0.00010 | $0.00144 |
Grade A, and why
setup-codebase-harness 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 9d 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 — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Set up the codebase harness
Harness engineering: the model is fixed — what you engineer is the scaffolding around it (the environment, the docs, the feedback loops) so an agent can build and verify software with minimal human attention. Humans steer; agents execute. Your job is to make the repo legible, executable, and verifiable.
Work incrementally and depth-first: assess what exists, build the one missing capability, use it to unlock the next. Don't boil the ocean — set up what the repo actually needs. When the agent struggles, the fix is almost never "try harder" — ask "what capability is missing, and how do I make it legible and enforceable?" and add it.
This skill orchestrates the focused sub-skills: dev-local-setup,
e2e-setup, crabbox-setup (cloud/parallel), and verifier-setup
(scaffolds a repo-specific /verify loop; supersedes the older pr skill).
0. Assess
Survey the repo: stack, package manager, services/ports, infra deps, existing docs/tests/CI, and the implicit rules (buried in READMEs, PR comments, people's heads). Note what's missing per pillar below.
1. Legible — the agent can reason about the repo
What the agent can't see doesn't exist. Knowledge in chat threads / heads is invisible — push it into versioned, repo-local artifacts.
- a) Map, not manual. Shrink the root agent doc (
AGENTS.md/CLAUDE.md) to a ~100-line table of contents: one-line overview, project tree, golden rules (the hard invariants), and a "where to look" table. Move the depth into a structureddocs/system-of-record (architecture, frontend, testing, domain topics) with adocs/index.md. A monolithic instruction file rots and crowds out the task — keep the map small and stable, disclose detail progressively. - b) Custom lints with remediation. Promote the prose golden rules into
mechanical checks — human taste captured once, enforced everywhere, every run.
One lint per invariant (layering / dependency direction, naming, no-
any, forbidden imports, file-size, structured logging). Write the error message to inject the fix ("X isn't allowed here — do Y") so the remediation lands in agent context. Wire them into the repo's linter + CI. - c) Queryable code graph. Index the repo with
codebase-memory-mcpso the agent traces callers, data flow, and architecture from a knowledge graph instead of blind grepping — faster, more precise navigation on large codebases. - d) (later) Keep docs honest. A freshness / doc-gardening pass that flags docs that no longer match the code and opens fix-up PRs.
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.
- 9d ago First seen · 101 lines · 103 tokens per session scan A 7722757f45e6
setup-codebase-harness is a skill published in the GitHub repository gabrielmoreira/agent-skills-mirror (17 stars, last pushed yesterday), licensed MIT. It adds 103 tokens to every session and 1,438 once invoked, about $0.0005 per session on Opus 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 2026-09-03.
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