Borrowing it
Nothing to install: this file belongs to yungwood/ical-filter-proxy. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/yungwood/ical-filter-proxy/main/AGENTS.mdgit clone --depth 1 https://github.com/yungwood/ical-filter-proxyWrote 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/instructions/yungwood/ical-filter-proxy/agents-md)<a href="https://agentmods.dev/instructions/yungwood/ical-filter-proxy/agents-md"><img src="https://agentmods.dev/badge/instructions/yungwood/ical-filter-proxy/agents-md/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.
<a href="https://agentmods.dev/instructions/yungwood/ical-filter-proxy/agents-md"><img src="https://agentmods.dev/badge/instructions/yungwood/ical-filter-proxy/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00523 | $0.00523 |
| Opus 5.5 | $0.00209 | $0.00209 |
| Sonnet 5.5 | $0.00105 | $0.00105 |
| Haiku 4.5 | $0.00052 | $0.00052 |
Grade A, and why
ical-filter-proxy 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 1mo 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 — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Notes
This file gives contributor agents enough project context to make focused changes without rediscovering the repo shape.
Project Shape
- This is a Go HTTP service that proxies upstream iCalendar feeds, filters events, and serves filtered calendar feeds.
- YAML-backed config types use a
Configsuffix where there is a separate runtime representation. - Runtime config is built in two phases:
LoadConfig(file)reads YAML, resolves secret files, and validates calendar-level settings.Config.Compile()buildsRuntimeConfig, compiles match rules, and rejects invalid regexes before serving.
- Keep the config/runtime split clear:
CalendarConfig -> CalendarFilterConfig -> FilterEventMatchRulesConfig -> EventMatchRulesStringMatchRuleConfig -> StringMatchRule
- Regex match rules should be compiled during config compilation, not during per-event processing.
- Transforms are not currently compiled;
StringTransformRuleis used directly at runtime.
Common Commands
Run the full test suite:
go test ./...
Run the configured linter:
go run github.com/golangci/golangci-lint/v2/cmd/[email protected] run --config .golangci.yml ./...
Run Dockerfile linting when touching container files:
hadolint Dockerfile
Run Nix checks when touching Nix files:
nix flake check
Contribution Preferences
- Keep PRs focused. Prefer small, reviewable changes over broad refactors.
- Follow existing naming and structure before introducing new abstractions.
- Add or update tests for behavior changes, especially config validation, HTTP handling, filtering, metrics, and security-sensitive code.
- Prefer returning errors from lower-level code and logging at the application boundary.
- Preserve security behavior around token handling, URL redaction, normalized metrics labels, and management endpoint separation.
- If adding new match condition types, add them through the config-to-runtime compilation path rather than doing repeated parsing during event processing.
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.
- 1mo ago First seen · 61 lines · 523 tokens per session scan A 2f595d21ab10
ical-filter-proxy AGENTS.md is an instructions file published in the GitHub repository yungwood/ical-filter-proxy (27 stars, last pushed yesterday), licensed MIT. It adds 523 tokens to every session, about $0.0021 per session on Opus 5.5. 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 2026-09-01.
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