This file is byte-identical to the first copy the registry indexed, one of 3 indexed copies. Same content hash, so the same checks give both the same grade.
diagnose from coder/agent-tty is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
Disciplined diagnosis loop for hard bugs and performance regressions. Reproduce → minimise → hypothesise → instrument → fix → regression-test. Use when user says "diagnose this" / "debug this", reports a bug, says something is broken/throwing/failing, or describes a performance regression.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Diagnose
A discipline for hard bugs. Skip phases only when explicitly justified.
When exploring the codebase, use the project's domain glossary to get a clear mental model of the relevant modules, and check ADRs in the area you're touching.
## Phase 1 — Build a feedback loop
**This is the skill.** Everything else is mechanical. If you have a fast, deterministic, agent-runnable pass/fail signal for the bug, you will find the cause — bisection, hypothesis-testing, and instrumentation all just consume that signal. If you don't have one, no amount of staring at code will save you.
Spend disproportionate effort here. **Be aggressive. Be creative. Refuse to give up.**
### Ways to construct one — try them in roughly this order
1. **Failing test** at whatever seam reaches the bug — unit, integration, e2e.
2. **Curl / HTTP script** against a running dev server.
3. **CLI invocation** with a fixture input, diffing stdout against a known-good snapshot.
4. **Headless browser script** (Playwright / Puppeteer) — drives the UI, asserts on DOM/console/network.
…
The line at the top of this page pins the label git:20260429.20f5c0a, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
GET https://markdownregistry.com/api/v1/artifacts/art_pbjgtlogerq6l6yr
GET https://markdownregistry.com/api/v1/resolve?ref=coder/agent-tty/diagnose
GET https://markdownregistry.com/api/v1/blob/28886402bbfa0470248086eab9106a103b964b76ae9496e63ff0c8a6761b6d13
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
coder/agent-tty · .agents/skills/codebase-design/SKILL.md · Shared vocabulary for designing deep modules. Use when the user wants to design or improve a module's interface, find…
coder/agent-tty · .agents/skills/diagnosing-bugs/SKILL.md · Diagnosis loop for hard bugs and performance regressions. Use when the user says "diagnose"/"debug this", or reports…
coder/agent-tty · .agents/skills/domain-modeling/SKILL.md · Build and sharpen a project's domain model. Use when the user wants to pin down domain terminology or a ubiquitous…
coder/agent-tty · .agents/skills/grill-with-docs/SKILL.md · A relentless interview to sharpen a plan or design, which also creates docs (ADR's and glossary) as we go.
coder/agent-tty · .agents/skills/grilling/SKILL.md · Interview the user relentlessly about a plan or design. Use when the user wants to stress-test a plan before building…
coder/agent-tty · .agents/skills/improve-codebase-architecture/SKILL.md · Scan a codebase for deepening opportunities, present them as a visual HTML report, then grill through whichever one you…
coder/agent-tty · .agents/skills/improve/SKILL.md · Survey any codebase as a senior advisor and produce prioritized, self-contained implementation plans for OTHER…
coder/agent-tty · .agents/skills/release-maintainer/SKILL.md · Internal maintainer SOP for version bumps, release PRs, tagging, publishing, and post-publish verification in this…
coder/agent-tty · .agents/skills/to-issues/SKILL.md · Break a plan, spec, or PRD into independently-grabbable issues on the project issue tracker using tracer-bullet…
coder/agent-tty · .agents/skills/to-prd/SKILL.md · Turn the current conversation into a PRD and publish it to the project issue tracker — no interview, just synthesis of…
coder/agent-tty · .agents/skills/triage/SKILL.md · Move issues and external PRs through a state machine of triage roles — categorise, verify, grill if needed, and write…
github/awesome-copilot · skills/diagnose/SKILL.md · Perform a systematic diagnostic scan of an AI workflow across 5 quality dimensions — prompt quality, context…
pedrohcgs/claude-code-my-workflow · .claude/skills/diagnose/SKILL.md · Root-cause a failing or wrong empirical result with a disciplined reproduce → minimise → hypothesise → instrument → fix…
kerberosclaw/kc_ai_skills · diagnose/SKILL.md · Use when the user reports misbehaving software to investigate — a bug, crash, wrong output, flaky behavior, or…
skillberry-ai/cap-evolve · skills/phases/diagnose/SKILL.md · Extract the learning signal from execution traces — the textual analogue of a gradient. Use between evaluation and…
mycelium-hq/ai-brain-starter · skills/diagnose/SKILL.md · Use when an AI Brain vault needs a health check or something feels off: Claude ignores CLAUDE.md, journal entries…
