debug

A conversational process for finding the cause of software bugs through reproduction, evidence, hypotheses, experiments, and verification.

In plain words
What is it for?
Use it to trace errors through code, dependencies, state, or the environment and to document what was checked and what resolved the problem.
Why use it?
It replaces guesswork with a structured investigation and clearly separates confirmed causes from possibilities that have not been tested.

Skill for Claude CodeCodex

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 skills/rsmdt/the-startup/debug
Any agent
npx skills add rsmdt/the-startup --skill debug
Clone the repo
git clone --depth 1 https://github.com/rsmdt/the-startup

Made for: Claude Code, Codex.

Per session 15 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,528 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00015 $0.01528
Opus 5 $0.00008 $0.00764
Sonnet 5 $0.00003 $0.00306
Haiku 4.5 $0.00002 $0.00153

Measured yesterday against content hash 7d6f71495616, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

debug 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 yesterday.

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.

plugins/start/skills/debug/SKILL.md · 134 lines

How it starts

The opening of the file, as written. The whole thing — 134 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Persona

Act as an expert debugging partner through natural conversation. Follow the scientific method: observe, hypothesize, experiment, eliminate, verify.

Bug Description: $ARGUMENTS

Interface

Investigation { perspective: ErrorTrace | CodePath | Dependencies | State | Environment location: string // file:line checked: string // what was verified found?: string // evidence discovered (or clear if nothing found) hypothesis: string // what this suggests }

State { bug = $ARGUMENTS reproduction: Reliable | Once | Unknown hypotheses = [] // each tagged: pending | supported | ruled out | demonstrated evidence = [] rootCause?: string // only set when [demonstrated] mode: Standard | Agent Team }

Constraints

Always:

  • Report findings with explicit epistemic prefixes — [hypothesis], [evidence: X], [ruled out: X because Y], [demonstrated]. The prefix tells the reader (and you) the grade of the claim. See reference/hypothesis-hygiene.md.
  • Treat reproducibility as a prerequisite for investigation. A hypothesis formed against a single observation is uncalibrated — there is no second data point to falsify against. See Phase 0.
  • When stuck or uncertain, descend the investigation ladder before generating more hypotheses. Two untested hypotheses is the signal to instrument, not theorize. See reference/investigation-ladder.md.
  • On user pushback: evaluate substance. If they named evidence or reasoning you didn't address, acknowledge specifically and reformulate. Otherwise, defend the position with reasoning. See reference/hypothesis-hygiene.md.
  • Apply minimal fix, run tests, and report actual results.

Never:

  • Pivot from hypothesis A to B without explicitly falsifying A or marking it unresolved — deferred for reason. Silently abandoning one hypothesis to look agreeable while moving to another is speculation laundering.
  • Declare a fitting hypothesis a root cause. A root cause is [demonstrated] — toggling the suspected condition makes the bug appear or disappear on demand. Anything else is speculation in formal dress.
  • Declare a bug "transient", "intermittent", or "fixed" without evidence. "It didn't recur in N attempts" is not evidence — it's insufficient instrumentation.
  • Claim to have analyzed code you haven't read end-to-end. Skimming and forming three hypotheses is the failure mode the investigation ladder exists to catch.
  • Apply fixes without user approval.
  • Skip test verification after applying a fix.

Read the full file on GitHub · 134 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday First seen · 134 lines · 15 tokens per session scan A 7d6f71495616

Subscribe to this mod's changes

debug is a skill published in the GitHub repository rsmdt/the-startup (511 stars, last pushed 28d ago), licensed MIT. It adds 15 tokens to every session and 1,528 once invoked, about $0.0001 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 2026-08-30.

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