Vero Spec Write

What it does

When your agent uses it

• Writing & Content work in your project

Example prompts

• “/vero-spec-write”

Requirements

• Python 3
• Pre-approved tools (allowed-tools): Read, Write, Edit, Bash, Grep, Glob

Workflow steps

6 steps, taken from the first numbered list in SKILL.md.

1. 1Every spec is def spec_ (impl : RepoImpl) : Prop := …. The parameter name may be _impl if unused.
2. 2Spec files contain only def spec_* and def spec_helper_* declarations. No theorem, lemma, example, axiom, instance, or !benchmark markers.
3. 3Spec bodies access APIs via impl.. — see /Bundle.lean for the field name (lowerCamelCase of the package name).
4. 4spec_helper_* defs (executable predicates referenced inside specs) live alongside the specs in the same module's Spec file, near the top.
5. 5Update manifest.json::packages[].modules[].specs[] with the bare-string names. Helpers go under the module's optional spec_helpers[] list.
6. 6For translated-source repos, record source provenance for each new

What it can do on your machine

Read from SKILL.md and the folder at commit 0a7325d. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Write
  • Edit
  • Bash
  • Grep
  • Glob

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are markdown and lean).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Vero Spec Write loads about 1.5k tokens when it runs. Until then it costs about 59 tokens; SKILL.md has 641 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~59

When it runs · the whole SKILL.md, loaded when a task matches

~1.5k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• NotePre-approves every shell command (allowed-tools: Bash)SKILL.md

  allowed-tools: Read, Write, Edit, Bash, Grep, Glob

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from sunblaze-ucb/vero at commit 0a7325d, republished under its Apache-2.0 licence (© sunblaze-ucb). 641 words, ~1,504 tokens.

name

vero-spec-write

description

Use during the spec_write stage to author specifications for translated Python (or new-source) projects in two substeps — reason about what specs should exist, then formalize them in Lean. Pair with vero-lean-pitfalls.

allowed-tools

Read, Write, Edit, Bash, Grep, Glob

## spec_<descriptive_name>

- **Module:** `<ModuleName>`
- **Covers APIs:** `f`, `g`
- **Intent (NL):** one paragraph plain English.
- **Lean sketch:**
  ```lean
  def spec_<name> (impl : RepoImpl) : Prop :=
    ∀ … , …  -- pseudocode is fine

If a spec needs a new helper predicate (used only inside specs), propose it under `## spec_helpers (proposed)` near the top of the plan.

End the file with a `## Coverage` table:

```markdown
| Module | API | Specs |
|---|---|---|
| Account | createAccount | spec_create_zero_balance, spec_create_exists |
| Account | closeAccount | spec_close_removes |

© sunblaze-ucb, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in .claude/skills/vero-spec-write of sunblaze-ucb/vero.

Open the folder on GitHubat commit 0a7325d