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 skills/kpavlov/tachyon/tachyon-developmentnpx skills add kpavlov/tachyon --skill tachyon-developmentgit clone --depth 1 https://github.com/kpavlov/tachyonWrote 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/skills/kpavlov/tachyon/tachyon-development)<a href="https://agentmods.dev/skills/kpavlov/tachyon/tachyon-development"><img src="https://agentmods.dev/badge/skills/kpavlov/tachyon/tachyon-development.svg" alt="Measured on agentmods" 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 | $0.00041 | $0.01813 |
| Opus 5 | $0.00020 | $0.00907 |
| Sonnet 5 | $0.00008 | $0.00363 |
| Haiku 4.5 | $0.00004 | $0.00181 |
Grade A, and why
tachyon-development 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 today.
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 — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Prime directives
- ATDD: prefer E2E, unit only for edge cases E2E can't cover. Start e2e tests before prod code.
- No
toString()as a serialization shortcut for structured/wire-facing content (resource results, prompt results, content-block mapping, anything that ends up in a JSON response).toString()on a record/POJO produces its debug form (Foo[bar=1]), not JSON — it silently corrupts the payload instead of failing loudly. Route structured values through the configuredPayloadSerializer/codec, or through a proper domain-to-domain mapping (e.g. one content-block type to its counterpart), even for the "shouldn't normally happen" fallback branch. ReservetoString()for values it's actually correct for:Stringpassthrough, numeric/boolean scalars, and well-specified formats likeInstant#toString()(RFC-3339). - Prefer an
importover a fully-qualified name. Fall back to FQN only where two same-named types are genuinely both referenced in one file, and then prefer FQN-ing just the side that isn't this module's own domain type, importing the other, rather than FQN-ing both out of caution. final varover explicit types. Usefinalfor fields/vars where possible.- Kotlin API refactors follow the adapter shapes in
docs/architecture/guidance.md. - Java
ServerBuilderis the implementation source of truth. Kotlin adds only thin adaptation for suspend lambdas and Kotlin-specific types; never duplicate validation or registration logic. - Treat
../../../examples/weather-mcpandexamples/weather-mcp-kotlinas Rosetta Stone examples. Keep their MCP features, metadata, behavior, and coverage functionally identical when changing either one. - Keep Kotlin source files focused. At more than 300 lines, consider splitting by owned responsibility before adding code.
- A public API change (new/changed method, param, wire field, or behavior contract like TTL/null
semantics) is not done until its docs are done: update the relevant file under
docs/, this skill, and/ordocs/architecture/guidance.mdin the same change. Don't defer it to a follow-up.
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.
- today Changed 58cb8dc79afa
- 6d ago First seen · 79 lines · 41 tokens per session scan A 67f4a649ebe8
tachyon-development is a skill published in the GitHub repository kpavlov/tachyon (30 stars, last pushed yesterday), licensed Apache-2.0. It adds 41 tokens to every session and 1,813 once invoked, about $0.0002 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 2026-08-30.
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