Neva is a statically typed programming language in which programs are message-passing graphs: nodes exchange data through ports and run concurrently by default. It is for developers building compiled programs with dataflow control, visual editing, and interoperability with Go. The catalogue includes skills and instructions for working with Neva.
Borrowing it
Nothing to install: this file belongs to nevalang/neva. 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/nevalang/neva/main/.codex/skills/neva-language/SKILL.mdgit clone --depth 1 https://github.com/nevalang/nevaWrote 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/nevalang/neva/neva-language)<a href="https://agentmods.dev/skills/nevalang/neva/neva-language"><img src="https://agentmods.dev/badge/skills/nevalang/neva/neva-language.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 | $0.00023 | $0.00261 |
| Opus 5 | $0.00012 | $0.00130 |
| Sonnet 5 | $0.00005 | $0.00052 |
| Haiku 4.5 | $0.00002 | $0.00026 |
Grade A, and why
neva-language 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 5d 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.
What it actually says
Neva Language
Use this skill for changes touching *.neva or Neva code snippets.
CLI Discovery
- Use
neva --helpto list commands and global options. - Use
neva <command> --helpbefore relying on a command's flags or argument contract. - During repository development, run
go run ./cmd/neva --helporgo run ./cmd/neva <command> --helpwhen a local binary is unavailable. neva doc [package/path] [.] <pattern>searches the bundled standard library; use it to discover existing components before adding one.
Rules
- Read
docs/user/style_guide.mdbefore editing. - Keep edited
.nevafiles syntactically valid. - If syntax is uncertain, consult
internal/compiler/parser/neva.g4and nearby.nevaexamples before editing. - When feasible, validate changed Neva programs by compiling or running them.
- When editing documentation or snippets, prefer a quick local compile/run check of an equivalent minimal example.
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.
- 5d ago First seen · 29 lines · 23 tokens per session scan A d8e999e5ef6f
neva-language is a skill published in the GitHub repository nevalang/neva (1,079 stars, last pushed 14d ago), licensed MIT. It adds 23 tokens to every session and 261 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 skills, from other repositories
pi-loop-forensics
Diagnose pi-go agent loops and degenerate turns — "agent loop aborted", runaway thinking with no tool calls, repeated phrases. Discriminates genuine model repetition collapse from a race, a tool-parse failure, or a too-low guard, and A/B replays a seed session across providers.
nightly-session-watch
Nightly sweep of the last 24h of pi-go sessions — anomalous runs, loop aborts, tool error rates, token waste, real prompt-token spend, and whether the observation and palace pipelines are still recording. Triages each finding to the specialist skill that diagnoses it. Use for an unattended daily health check, or on…
kessoku-di
Kessoku compile-time DI with parallel initialization for Go. Use when writing or debugging kessoku providers/injectors, enabling async dependencies, migrating from google/wire, or fixing go:generate/codegen issues in Go services.
lsp-cross-repo
Cross-repository analysis — find all callers of a library symbol in one or more consumer repos. Use when refactoring a shared library and need to understand how consumers use it.
lsp-implement
Find all concrete implementations of an interface or abstract type. Use when you need to know what types satisfy an interface, or what subtypes exist before changing a base type.
sounio-lint
Scan a .sio file for Rust-isms and suggest Sounio-native fixes.