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/dbwls99706/deadends.dev/claude-mdgit clone --depth 1 https://github.com/dbwls99706/deadends.devWhat 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 | $0.03923 | $0.03923 |
| Opus 5 | $0.01962 | $0.01962 |
| Sonnet 5 | $0.00785 | $0.00785 |
| Haiku 4.5 | $0.00392 | $0.00392 |
Grade A, and why
deadends.dev CLAUDE.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 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.
How it starts
The opening of the file, as written. The whole thing — 322 lines — stays where its author put it; the contents beside it link to each section on GitHub.
deadends.dev
Structured failure knowledge database for AI agents - covering both code errors AND country-specific real-world dead ends. 2,393+ ErrorCanon JSON entries across 54 domains:
- 51 code-error domains (2,089 entries): python, node, docker, cuda, git, pip, typescript, rust, go, kubernetes, terraform, aws, nextjs, react, java, database, cicd, php, dotnet, networking, android, api, cloud, cmake, elasticsearch, embedded, flutter, grpc, huggingface, kafka, llm, mongodb, nginx, opencv, pytorch, redis, ros2, tensorflow, unity, + quirk domains (communication, culture, data, disaster, food-safety, legal, medical, mental-health, pet-safety, policy, safety, security).
- 3 new country-scoped domains (
visa,banking,emergency) plus existing non-code domains extended with country-scoped canons. ID format{domain}/{slug}/{country}where country is an ISO 3166-1 alpha-2 code (kr,jp,us,de,uk,fr,cn,hk,tw,th,in,vn,id,sg,ph,sa,ae,tr,il,ru,br,mx, ...). 52 countries, 300+ country-scoped entries as of v0.10.
Country-canon rationale: coding dead ends are largely solved by modern LLMs. Country-specific rules (visa caveats, jurisdictional laws, cultural taboos, food safety, emergency numbers, housing contract quirks) are where generic AI advice is most often wrong. The expansion fills this gap with primary-source-cited structured entries.
Architecture
data/
canons/ # ErrorCanon JSON files (source of truth, 2393+ files)
{domain}/ # One directory per domain (54 domains)
{slug}_{env}.json # Flat-file format (code: env = runtime-os)
{slug}/{env}.json # Directory-style format
# For country canons: env = ISO alpha-2 code (kr, jp, ...)
environments/ # Environment matrix (env_matrix.json)
graph/ # Error transition graph data
signatures/ # Error signature data
generator/
__init__.py
build_site.py # Static site builder (Jinja2 templates → site/)
bulk_generate.py # Generate canon JSON from seed definitions (current version)
# Historical versions v2-v16 live under archive/bulk_generate_history/
collect_evidence.py # Evidence collection utilities
collect_signatures.py # Signature collection utilities
domains.py # Domain constants: KEYWORD_MAP, DOMAIN_DISPLAY_NAMES, suggest_domains()
generate_canons.py # Canon generation logic
generate_pairs.py # Pair generation utilities
lookup.py # Programmatic error lookup SDK (lookup, lookup_all, search, batch_lookup)
ping_search_engines.py # Search engine ping on deploy
pipeline.py # Unified pipeline: validate → generate → build → test
reverify.py # Assigns each content cycle a disjoint bucket of aging
# canons to re-verify (see 'Re-verifying Aging Canons')
schema.py # ErrorCanon JSON Schema (ERRORCANON_SCHEMA)
submit_indexnow.py # IndexNow submission on deploy
templates/ # Jinja2 HTML templates
index.html # Homepage
domain.html # Domain listing page
error_summary.html # Error summary page (groups environments)
page.html # Individual error page (per environment)
search.html # Search page
validate.py # Validation: schema, business rules, HTML, cross-refs, staleness
mcp/
server.py # MCP server (JSON-RPC over stdio) - 11 tools for AI agents
api/
mcp.py # Vercel serverless MCP endpoint
site/ # Generated static site output (DO NOT edit directly)
tests/ # pytest test suite
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 · 322 lines · 3,923 tokens per session scan A 0c76afe31f9e
deadends.dev CLAUDE.md is an instructions file published in the GitHub repository dbwls99706/deadends.dev (0 stars, last pushed yesterday), licensed MIT. It adds 3,923 tokens to every session, about $0.0196 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 instructions, from other repositories
cloakbrowser-mcp AGENTS.md
Instructions for swimmwatch/cloakbrowser-mcp, covering agents.md, about the project, golden rules, project layout and daily commands.
KACHOW-Teknofest-2026 AGENTS.md
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cloakbrowser-mcp copilot-instructions.md
Instructions for swimmwatch/cloakbrowser-mcp: Follow AGENTS.md for project-wide coding, testing, documentation, changelog, and commit rules.
GuideAnts copilot-instructions.md
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server copilot-instructions.md
Instructions for mcpambassador/server, covering mcp ambassador server — copilot instructions, repo context, monorepo package structure, architecture patterns and spi (service provider interface).
server AGENTS.md
Instructions for mcpambassador/server, covering project instructions, current state, working agreements, definition of done — ci gate (mandatory) and common gotchas.