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 agentmods add skills/hoatv2211/gamestudio-codexkit/evidence-first-debuggingnpx skills add hoatv2211/GameStudio-CodexKIT --skill evidence-first-debugginggit clone --depth 1 https://github.com/hoatv2211/GameStudio-CodexKITWrote 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/hoatv2211/gamestudio-codexkit/evidence-first-debugging)<a href="https://agentmods.dev/skills/hoatv2211/gamestudio-codexkit/evidence-first-debugging"><img src="https://agentmods.dev/badge/skills/hoatv2211/gamestudio-codexkit/evidence-first-debugging.svg" alt="Measured on agentmods" 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 | $0.00063 | $0.00878 |
| Opus 5 | $0.00032 | $0.00439 |
| Sonnet 5 | $0.00013 | $0.00176 |
| Haiku 4.5 | $0.00006 | $0.00088 |
Grade A, and why
evidence-first-debugging 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 5d 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 — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Evidence-First Debugging
Overview
Find the root cause before changing code. A fix is complete only when the original symptom is reproduced, isolated, repaired minimally, and guarded by regression evidence.
When to use
Use for crashes, wrong behavior, failing tests, startup problems, packet mismatches, offline failures, build errors, or unexpected generated output.
When NOT to use
Do not use for open-ended feature design, routine build verification, broad code review, or mutation without a reproducible symptom.
Required inputs and context discovery
Collect exact symptom, expected behavior, reproduction steps, frequency, environment, first failing version or commit when known, logs, relevant ownership boundaries, and safe instrumentation options.
Safety and risk level
Inspection and instrumentation are preferred. Any mutation follows test-first discipline and exact file ownership; database, services, assets, or external projects need separate safety approval.
Workflow
- Reproduce the symptom with the smallest deterministic command or fixture. Completion criterion: failure occurs for the expected reason, or reproduction is BLOCKED with evidence.
- Trace the data and control path from observed failure toward its source. Completion criterion: component boundaries and the first incorrect state are identified.
- Rank hypotheses and add minimal instrumentation that distinguishes them. Completion criterion: one hypothesis is supported and alternatives are weakened by output.
- Write a failing regression test or executable check before the fix. Completion criterion: the check fails on the original behavior.
- Apply the smallest root-cause fix and rerun the focused check. Completion criterion: the focused check passes without weakening assertions.
- Run adjacent and broader verification, then record limitations. Completion criterion: regressions are checked or explicitly BLOCKED.
Evidence and output contract
Produce reproduction command, failure output, hypothesis table, instrumentation evidence, changed files, regression test, verification commands, verdict, and limitations.
What ships with it
1 file 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.
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.
- 5d ago First seen · 85 lines · 63 tokens per session scan A 76ce669c7dca
evidence-first-debugging is a skill published in the GitHub repository hoatv2211/GameStudio-CodexKIT (3 stars, last pushed 2d ago), licensed MIT. It adds 63 tokens to every session and 878 once invoked, about $0.0003 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 2026-08-31.
Other skills, from other repositories
deep-discovery
Use when the user asks for deep discovery, 100-question brainstorming, idea interrogation, architecture stress testing, strategy vetting, weakness finding, hole-poking, exhaustive exploration, planning or auditing Codex plugins or skills, or pre-commitment review of a design, plan, strategy, architecture, product…
prewalk
Use when the user wants a coding task executed with a strong planner model first and a faster/cheaper executor model after the first successful implementation edit.
registry-broker-orchestrator
Use Registry Broker to discover and summon specialist agents for focused subtasks from inside Codex.
codex-sdd:customize
Guide for injecting custom MCP tools, skills, and hook points into the OpenSpec workflow for team-specific processes.
codex-sdd:validate
Check implementation alignment with specification, detect drift between planned design and actual code. Fourth phase of OpenSpec workflow.
codex-sdd:archive
Preserve change artifacts (proposal, design, tasks) into structured archive and update knowledge base. Final phase of OpenSpec workflow.