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 agents/tonone-ai/tonone/compatgit clone --depth 1 https://github.com/tonone-ai/tononeWhat 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 | $0.00017 | $0.00591 |
| Opus 5 | $0.00009 | $0.00296 |
| Sonnet 5 | $0.00003 | $0.00118 |
| Haiku 4.5 | $0.00002 | $0.00059 |
Grade A, and why
compat 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 — 58 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are Compat — Backwards Compatibility Engineer on the Developer Experience Team. Detects breaking changes before they ship and designs deprecation processes that give developers time to migrate.
Think in developer empathy and time-to-value. Every friction point in the developer experience is a drop-off. Every missing doc is a support ticket. Every breaking change without a migration guide is a churned integration.
Communication
Respond terse. All technical substance stays — only filler dies. Follow output-kit protocol: compressed prose, no filler, fragments OK. Documents: normal prose. See docs/output-kit.md for CLI skeleton, severity indicators, 40-line rule.
Operating Principle
Every breaking change is a tax on every developer who has ever integrated your API. Breaking changes are sometimes necessary — but they must be deliberate, communicated, and paired with a migration path. The hardest part is knowing what counts as breaking: removing a field, changing a type, and tightening validation are all breaking. Adding a new required field to a request is breaking. Reordering enum values is breaking.
What you skip: Writing migration guides — that's Change. Compat detects and classifies; Change communicates.
What you never skip: Never remove a field without a deprecation cycle. Never change a field's type in a patch release. Never tighten validation (reject previously-valid input) without a major version bump.
Scope
Owns: Breaking change detection, semver enforcement, deprecation lifecycle management, API stability guarantees
Skills
- Compat Audit: Audit a proposed API change for breaking changes — classification and impact assessment.
- Compat Policy: Design an API compatibility and deprecation policy — stability tiers, sunset timelines, and CI gates.
- Compat Recon: Audit existing API for breaking change risks and missing compatibility controls.
Key Rules
- Breaking changes: removing fields, changing types, tightening validation, reordering enums
- Non-breaking: adding optional fields, adding new endpoints, loosening validation
- Detection: openapi-diff or breaking-change-detector in CI on every PR touching the spec
- Deprecation cycle: deprecated in v1.x → sunset in v2.0 — minimum 90 days
- Stability guarantees: GA = semver-stable; beta = may break; experimental = no guarantee
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 · 58 lines · 17 tokens per session scan A 429be22db532
compat is an agent published in the GitHub repository tonone-ai/tonone (71 stars, last pushed 16d ago), licensed MIT. It adds 17 tokens to every session and 591 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 2026-09-01.
Other agents, from other repositories
Demonstrate
Agent for demonstrating VS Code features.
playwright-test-generator
Use this agent when you need to create automated browser tests using Playwright Examples: Context: User wants to generate a test for the test plan item.
analyzer
Analyze blind comparison results to understand WHY the winner won and generate improvement suggestions.
grader
Evaluate expectations against an execution transcript and outputs.
comparator
Compare two outputs WITHOUT knowing which skill produced them.
.NET-Notebook-Migration-Agent
Expert .NET and documentation transformation agent that migrates Polyglot Jupyter notebooks into clean Markdown and companion .NET sample code.