loom-omission-hunter

loom-omission-hunter is a skill for Claude Code from xiqin/loom. It costs 105 tokens per session (1,311 once invoked), scanned A, original, MIT.

A read-only code reviewer that searches for required behavior that is missing, including missing tests, safeguards, side effects, failure handling, or public API updates.

In plain words
What is it for?
Use it after code and tests exist to check requirements against code references, tests, permissions, failure cases, and expected changes.
Why use it?
It helps find gaps that happy-path tests and the implementation author’s own review may overlook.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Part of the loom-engineering plugin — 22 skills shipped together

Good fit Use it after code and tests exist to check requirements against code references, tests, permissions, failure cases, and expected changes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/xiqin/loom/loom-omission-hunter
View source ↗ xiqin/loom
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.

Any agent
npx skills add xiqin/loom --skill loom-omission-hunter
Clone the repo
git clone --depth 1 https://github.com/xiqin/loom

Made for: Claude Code.

Or install loom-engineering, the plugin that ships this one along with the rest of its 22 skills.

Wrote 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.

agentmods badge for loom-omission-hunter

README.md
[![agentmods](https://agentmods.dev/badge/skills/xiqin/loom/loom-omission-hunter/github.svg)](https://agentmods.dev/skills/xiqin/loom/loom-omission-hunter)
Your own site
<a href="https://agentmods.dev/skills/xiqin/loom/loom-omission-hunter"><img src="https://agentmods.dev/badge/skills/xiqin/loom/loom-omission-hunter/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for loom-omission-hunter

Your own site · 80×15
<a href="https://agentmods.dev/skills/xiqin/loom/loom-omission-hunter"><img src="https://agentmods.dev/badge/skills/xiqin/loom/loom-omission-hunter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 105 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,311 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00105 $0.01311
Opus 5 $0.00053 $0.00656
Sonnet 5 $0.00021 $0.00262
Haiku 4.5 $0.00011 $0.00131

Measured 10d ago against content hash d38980538d74, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

loom-omission-hunter 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 10d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/omission-hunt.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/loom-omission-hunter/SKILL.md · 104 lines

How it starts

The opening of the file, as written. The whole thing — 104 lines — stays where its author put it; the contents beside it link to each section on GitHub.

遗漏猎人(omission-hunter)

触发条件

  • executing 已产出代码与 test-report.md,但 loom-converge 之前或之后需要一次专门寻找"应存在但不存在"的对抗式审查。
  • 怀疑实现只覆盖了 happy-path,边界/权限/失败/禁止行为可能被漏掉。
  • 需要独立视角,不依赖实现 agent 的自我报告。

非触发条件

  • 还没有代码或测试可审查。
  • quickfix / chore 等无 spec 的流程。

执行流程

Step 1:运行遗漏猎人

调用 loom MCP 工具 loom_omission_hunt(参数 spec_dir)。

工具只读检查 requirements.jsontraceability.json,对每个 behavior 做负空间检查,输出 findings/omission-hunter.json。返回 ok:false 表示有 blocker,需回流到 loom-converge

说明:scripts/omission-hunt.mjs 是该工具的实现,运行在 loom MCP 服务器进程内。不要在用户项目里用 node skills/... 调用(部署后路径会断裂)。

Step 2:对每个 Behavior 做负空间检查

对每个 REQ-xxx-Bnn,对照 requirements.jsoncategoryacceptance,检查以下"应存在但不存在":

  1. 代码符号:behavior 应在某个代码符号中实现。若 traceability.jsoncode_refs 或引用的符号不存在,报 missing code reference
  2. 测试:behavior 应有对应测试。若 traceability.jsontests 或测试文件不存在,报 missing test
  3. 预期副作用:涉及写/状态变更的 behavior 应有可观察的副作用(日志、事件、DB 记录)。若代码没有对应日志/事件/写入,报 missing expected side effect
  4. 禁止副作用forbidden-behavior category 的 behavior 应有保护代码(权限检查、限流、输入校验)。若保护缺失,报 missing forbidden-behavior guard
  5. 失败场景:涉及外部依赖的 behavior 应有超时/重试/回滚。若没有,报 missing failure handling
  6. 公共 API 变更:若 diff 修改了公共 API,但 requirements.json 没有 compatibility 类型 behavior,报 unrequested public API change
  7. 不变量保护:涉及并发/原子性的 behavior 应有锁/事务/CAS。若没有,报 missing invariant guard
  8. 可观测性observability 类型的 behavior 应有指标/日志/trace。若没有,报 missing observability

Step 3:生成 findings

每条 finding 形如:

{
  "id": "F-omit-001",
  "kind": "missing",
  "severity": "blocker",
  "message": "REQ-001-B03 (authorization) expects a permission check, but no guard code found in UserService.update",
  "requirement_id": "REQ-001",
  "behavior_id": "REQ-001-B03",
  "artifact": "src/services/user-service.js",
  "location": { "file": "src/services/user-service.js", "symbol": "update" },
  "suggested_fix": { "action": "create_task", "details": "add authorization guard to UserService.update" }
}

Read the full file on GitHub · 104 lines

Files

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.

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. 10d ago First seen · 104 lines · 105 tokens per session scan A d38980538d74

Subscribe to this mod's changes

loom-omission-hunter is a skill published in the GitHub repository xiqin/loom (5 stars, last pushed 1mo ago), licensed MIT. It adds 105 tokens to every session and 1,311 once invoked, about $0.0005 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.