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 instructions/dalmasonto/umbral/agents-mdgit clone --depth 1 https://github.com/dalmasonto/umbralWhat 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 | $0.00651 | $0.00651 |
| Opus 5 | $0.00326 | $0.00326 |
| Sonnet 5 | $0.00130 | $0.00130 |
| Haiku 4.5 | $0.00065 | $0.00065 |
Grade A, and why
umbral AGENTS.md 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 3d 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.
This is a copy
81% identical to claude-code-trace AGENTS.md — 67 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 44 lines — stays where its author put it; the contents beside it link to each section on GitHub.
GitNexus — Code Intelligence
This project is indexed by GitNexus as umbral (24987 symbols, 54141 relationships, 300 execution flows). Use the GitNexus MCP tools to understand code, assess impact, and navigate safely.
If any GitNexus tool warns the index is stale, run
npx gitnexus analyzein terminal first.
Always Do
- MUST run impact analysis before editing any symbol. Before modifying a function, class, or method, run
gitnexus_impact({target: "symbolName", direction: "upstream"})and report the blast radius (direct callers, affected processes, risk level) to the user. - MUST run
gitnexus_detect_changes()before committing to verify your changes only affect expected symbols and execution flows. - MUST warn the user if impact analysis returns HIGH or CRITICAL risk before proceeding with edits.
- When exploring unfamiliar code, use
gitnexus_query({query: "concept"})to find execution flows instead of grepping. It returns process-grouped results ranked by relevance. - When you need full context on a specific symbol — callers, callees, which execution flows it participates in — use
gitnexus_context({name: "symbolName"}).
Never Do
- NEVER edit a function, class, or method without first running
gitnexus_impacton it. - NEVER ignore HIGH or CRITICAL risk warnings from impact analysis.
- NEVER rename symbols with find-and-replace — use
gitnexus_renamewhich understands the call graph. - NEVER commit changes without running
gitnexus_detect_changes()to check affected scope.
Resources
| Resource | Use for |
|---|---|
gitnexus://repo/umbral/context |
Codebase overview, check index freshness |
gitnexus://repo/umbral/clusters |
All functional areas |
gitnexus://repo/umbral/processes |
All execution flows |
gitnexus://repo/umbral/process/{name} |
Step-by-step execution trace |
CLI
| Task | Read this skill file |
|---|---|
| Understand architecture / "How does X work?" | .claude/skills/gitnexus/gitnexus-exploring/SKILL.md |
| Blast radius / "What breaks if I change X?" | .claude/skills/gitnexus/gitnexus-impact-analysis/SKILL.md |
| Trace bugs / "Why is X failing?" | .claude/skills/gitnexus/gitnexus-debugging/SKILL.md |
| Rename / extract / split / refactor | .claude/skills/gitnexus/gitnexus-refactoring/SKILL.md |
| Tools, resources, schema reference | .claude/skills/gitnexus/gitnexus-guide/SKILL.md |
| Index, status, clean, wiki CLI commands | .claude/skills/gitnexus/gitnexus-cli/SKILL.md |
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.
- 3d ago First seen · 44 lines · 651 tokens per session scan A 5494f155de66
umbral AGENTS.md is an instructions file published in the GitHub repository dalmasonto/umbral (11 stars, last pushed 16d ago), licensed Apache-2.0. It adds 651 tokens to every session, about $0.0033 per session on Opus 5. A static security scan graded it A with 0 findings. It is 81% identical to claude-code-trace AGENTS.md, differing in 67 lines, and is treated as a copy.
Other instructions, from other repositories
angular AGENTS.md
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kui CLAUDE.md
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kui AGENTS.md
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vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.