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/jxoesneon/ciel/diff_patchnpx skills add jxoesneon/Ciel --skill diff_patchgit clone --depth 1 https://github.com/jxoesneon/CielWhat 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 | $0.00013 | $0.00266 |
| Opus 5 | $0.00006 | $0.00133 |
| Sonnet 5 | $0.00003 | $0.00053 |
| Haiku 4.5 | $0.00001 | $0.00027 |
Grade A, and why
diff_patch 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.
What it actually says
diff_patch
Unified diffs + patch application.
Operations
diff.create(a_path, b_path)/diff.from_strings(a, b).patch.apply(path, patch, strict=true).patch.conflict(path, patch)— detects without applying.patch.three_way(ours, theirs, base)— textual 3-way merge.
I/O Contract
io_contract:
input: { op, args }
output: { result, "conflicts?" }
idempotent: for_same_inputs
side_effects: [fs]
Use
self_improvement/ uses this to construct and apply mutation diffs.
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.
- yesterday First seen · 37 lines · 13 tokens per session scan A 681420345449
diff_patch is a skill published in the GitHub repository jxoesneon/Ciel (1 stars, last pushed yesterday), licensed Apache-2.0. It adds 13 tokens to every session and 266 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 2026-08-31.
Other skills, from other repositories
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review-documentation
Reviews the accuracy and writing quality of documentation. Use when reviewing doc changes in a diff, checking a new or edited page, or auditing the documentation of a codebase.
review-behaviors
Reviews the quality and coherence of behavior statements. Use when reviewing behavior changes in a diff, checking a new or edited behavior statement, or auditing the behavior statements of a codebase.
review-skills
Reviews Agent Skills. Use when auditing skills in a codebase, checking a new or edited SKILL.md, or verifying that a skill follows the Agent Skills spec.
review-tests
Reviews test quality and coverage. Use when checking that a diff has adequate tests, checking a new or edited test, or auditing the test suite of a codebase.
testing-rate-limiting
Apply deterministic SlowAPI rate-limiter isolation for FastAPI transport tests, especially to avoid flaky HTTP 429 responses.