F* is a proof-oriented programming language for writing software alongside formal specifications and machine-checked proofs. It is used for verified programming and theorem proving, with editor support for interactive development. The catalogue includes an agent that helps work with F* and Pulse.
Borrowing it
Nothing to install: this file belongs to FStarLang/FStar. 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/FStarLang/FStar/master/.github/agents/FStarDev.mdgit clone --depth 1 https://github.com/FStarLang/FStarWrote 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/agents/fstarlang/fstar/fstardev)<a href="https://agentmods.dev/agents/fstarlang/fstar/fstardev"><img src="https://agentmods.dev/badge/agents/fstarlang/fstar/fstardev/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/agents/fstarlang/fstar/fstardev"><img src="https://agentmods.dev/badge/agents/fstarlang/fstar/fstardev.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 | $0.00019 | $0.05111 |
| Opus 5.5 | $0.00008 | $0.02044 |
| Sonnet 5.5 | $0.00004 | $0.01022 |
| Haiku 4.5 | $0.00002 | $0.00511 |
Grade A, and why
FStarDev 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 12d 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 — 459 lines — stays where its author put it; the contents beside it link to each section on GitHub.
FStarDev Agent
Agent Identity
An expert F* compiler developer. This agent modifies the F* compiler sources, navigates the multi-stage bootstrap build, and validates changes through incremental rebuilds and testing. It covers compiler internals (parser, typechecker, extraction, SMT encoding, tactics), the Pulse checker plugin (stage 3), the build system (Make + dune), and the bootstrap/snapshot workflow.
Repository Layout
FStar/
├── src/ # F* compiler sources (written in F*)
│ ├── basic/ # Core utilities, options, errors, platform
│ ├── syntax/ # AST definitions, free variables, substitution
│ ├── parser/ # Surface syntax AST, dependency analysis
│ ├── tosyntax/ # Desugaring: surface AST → core AST
│ ├── typechecker/ # Type inference, checking, normalization, NBE
│ ├── smtencoding/ # Encoding to SMT (Z3) queries
│ ├── tactics/ # Tactic engine, metaprogramming primitives
│ ├── reflection/ # Reflection API builtins
│ ├── interactive/ # IDE protocol, incremental checking
│ ├── prettyprint/ # A pretty-printer library (François Pottier's pprint)
│ ├── fstar/ # Top-level driver (FStarC.Main, FStarC.Universal)
│ ├── tests/ # Compiler unit tests (OCaml)
│ ├── ml/ # Hand-written OCaml: system utils
│ ├── class/ # Typeclasses used in the compiler
│ ├── data/ # Data structures used in the compiler
├── ulib/ # F* standard library (verified .fst/.fsti files)
├── stage0/ # OCaml snapshot: starting point for bootstrapped build.
├── stage1/ # Built from: stage0 checks+extracts src/ → OCaml → dune build
├── stage2/ # Built from: stage1 checks+extracts src/ → OCaml → dune build
├── stage3/ # Stage2 + Pulse plugin linked in
├── pulse/ # Pulse language implementation
│ ├── src/checker/ # Pulse typechecker (F* source, extracted to OCaml plugin)
│ ├── src/syntax_extension/ # Pulse syntax desugaring; F* implementations of
│ │ # Pulse.RuntimeUtils / Pulse.Extract.CompilerLib
│ ├── lib/ # Pulse standard library (common/, pulse/)
│ ├── mk/ # Build infrastructure (test.mk, common.mk, locate.mk)
│ ├── test/ # Pulse tests
│ └── share/pulse/examples/ # Pulse examples
├── karamel/ # KaRaMeL submodule (F*/Pulse → C extraction)
├── mk/ # Top-level build infrastructure makefiles
├── tests/ # F* integration tests
├── examples/ # F* examples
└── doc/ # Documentation, book
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.
- 12d ago Changed · +1 lines 473272c2d3f0
- 19d ago Changed · -1 lines 887ec3ae20ce
- 24d ago Changed · -1 lines 13abc1f6a5df
- 2mo ago First seen · 460 lines · 19 tokens per session scan A a60bf3e09747
FStarDev is an agent published in the GitHub repository FStarLang/FStar (3,131 stars, last pushed today), licensed Apache-2.0. It adds 19 tokens to every session and 5,111 once invoked, about $0.0001 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 2026-08-30.
Other agents, from other repositories
fixture-reviewer
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func-verifier
RAT audit protocol (condensed; dev source: plugindocs/agent-lib/audit-output-protocol.md — plugin-internal, do NOT Read it at runtime).
p5s-func-verify-orchestrator
Tier 3 functional verification orchestrator. Manages pipelined cocotb TB generation, multi-seed parallel regression, incremental coverage analysis, waveform failure diagnosis, and Requirement Traceability Matrix generation.
ppa-optimizer-dc-orchestrator
Coordinator for one PPA optimization iteration. Sequences DC synthesis, report parsing, RTL patching, equivalence, smoke regression, delta computation, and convergence verdict. Self-contained; spawned by rtl-ppa-optimize-dc or rat-ultraloop-ppa skill.
symfony-tdd-coach
Guides TDD workflow for Symfony projects using Pest PHP or PHPUnit. Drives strict RED-GREEN-REFACTOR cycles with proper test isolation, Foundry factories, and regression protection. Use when writing tests, adding test coverage, or practicing TDD.