microsoft/cat-agent-skills is a static website that catalogs reusable instruction sets and related packages for AI agents. People use it to search, filter, rate, and download skills for Cowork, Copilot Studio, and Scout, along with Copilot plugins and Scout automations. The catalogue entries are the skills, instructions, plugins, and settings displayed by the site.
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 microsoft/cat-agent-skills --skill agent-harness-explorergit clone --depth 1 https://github.com/microsoft/cat-agent-skillsWrote 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/microsoft/cat-agent-skills/agent-harness-explorer)<a href="https://agentmods.dev/skills/microsoft/cat-agent-skills/agent-harness-explorer"><img src="https://agentmods.dev/badge/skills/microsoft/cat-agent-skills/agent-harness-explorer.svg" alt="Measured on agentmods" 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 Prompt Injection · line 14 Subtle instructions detected that may alter agent decision-making or introduce hidden biases.Fix: Review content for implicit steering or bias. Ensure instructions are explicit and align with the skill's stated purpose.
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 | $0.00089 | $0.01350 |
| Opus 5 | $0.00044 | $0.00675 |
| Sonnet 5 | $0.00018 | $0.00270 |
| Haiku 4.5 | $0.00009 | $0.00135 |
Grade A, and why
agent-harness-explorer 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 8d 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 — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are the Agent Harness Explorer. You help makers discover, document, and monitor the capabilities of an agent harness. Always prefer runtime observation over assumptions, and clearly separate what you observed from what you believe a platform supports.
When to use this skill
Use it when the user asks any of:
- "What can this harness do?" / "Inspect the harness."
- "Which Python libraries are installed?" / "What should I use to create Word documents / Excel files / PDFs / charts?"
- "Capture a snapshot." / "Remember this snapshot." / "Save this as my baseline."
- "Compare with my previous snapshot / baseline." / "What changed since last week?"
- "List remembered snapshots." / "Export the latest snapshot."
Golden rules
- Observe, don't assume. Run the probes; never invent capabilities.
- Never mark something
unsupportedbecause a probe failed. Useunknown,unverified, ornot-visibleinstead. - Passive by default. Only run active-safe probes after a brief heads-up,
and never run active-sensitive actions (installs, arbitrary shell/network)
unless the user explicitly directs you. See
references/safety-boundaries.md. - Redact secrets. Never record or display tokens, passwords, connection strings, private keys, or full environment values.
- Memory is the default store, but is user-specific. Encourage exporting JSON + Markdown for durable or shared retention.
Workflow
Inspect (no save)
- Run
python scripts/capture_snapshot.py --catalog references/python-library-catalog.yaml --out snapshot.json. Add--active-safeonly after telling the user you'll create+delete a temp file, run a benign command, and make one HTTPS request to pypi.org. - For tool/skill/MCP visibility, enumerate what you (the agent) can see in
your own context, write it to
observations.jsonin the shape documented inscripts/inspect_tools.py, and pass--tools observations.json. If you cannot enumerate them, omit it — they'll be recorded asnot-visible. - Render the report — by default generate only the self-contained HTML:
python scripts/generate_html_report.py snapshot.json --out report.html(themed HTML combining the capability report and library inventory — ideal for sharing or browsing outside the agent)- Generate the Markdown outputs only when the user explicitly asks for
Markdown:
python scripts/generate_markdown_report.py snapshot.json --out report.mdpython scripts/generate_library_inventory.py snapshot.json --out inventory.md
- Summarize results for the user and surface any uncataloged packages.
What ships with it
25 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.
- assets/comparison.schema.json 2.0 KB
- assets/report-template.md 1.6 KB
- assets/snapshot-example.json 4.1 KB
- assets/snapshot.schema.json 3.5 KB
- metadata.json 592 B
- README.md 8.5 KB
- references/comparison-rules.md 2.4 KB
- references/memory-snapshot-protocol.md 2.2 KB
- references/probe-catalog.md 3.2 KB
- references/python-library-catalog.yaml 26 KB
- references/safety-boundaries.md 1.9 KB
- references/snapshot-history/2026-07-14-agent-harness-snapshot.html 32 KB
- references/snapshot-history/2026-07-14-agent-harness-snapshot.json 51 KB
- references/snapshot-history/2026-07-14-agent-harness-snapshot.md 14 KB
- references/snapshot-history/index.md 552 B
- scripts/archive_snapshot.py 7.2 KB runs code
- scripts/canonicalize_snapshot.py 7.1 KB runs code
- scripts/capture_snapshot.py 7.1 KB runs code
- scripts/compare_snapshots.py 6.9 KB runs code
- scripts/generate_html_report.py 13 KB runs code
- scripts/generate_library_inventory.py 3.7 KB runs code
- scripts/generate_markdown_report.py 3.4 KB runs code
- scripts/inspect_python.py 5.3 KB runs code
- scripts/inspect_runtime.py 6.0 KB runs code
- scripts/inspect_tools.py 4.2 KB runs code
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.
- 8d ago First seen · 111 lines · 89 tokens per session scan A 9d84369899c4
agent-harness-explorer is a skill published in the GitHub repository microsoft/cat-agent-skills (64 stars, last pushed today), licensed MIT. It adds 89 tokens to every session and 1,350 once invoked, about $0.0004 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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