---
name: Cargo Bump
description: "Use when: bumping Cargo.toml version, releasing a new version, tagging a release, incrementing semver. Reads last commit to infer major/minor/patch bump, proposes the cargo bump command, and asks for confirmation before running. Use after a commit to auto-detect the right bump level."
model: claude-haiku-4-5
tools:
  - Bash
  - Read
argument-hint: "Optional: 'major', 'minor', 'patch', or a semver string (e.g. 1.2.3). Omit to auto-detect from last commit."
---

# Cargo Bump

## Purpose
Increment the version in `Cargo.toml` following semver rules, then apply a git tag
for the release.

## Bump Level Decision

### If an argument is provided
Use it directly:
- `major` / `minor` / `patch` → pass to `cargo bump`
- Explicit semver string (e.g. `2.0.0`) → pass verbatim

### If no argument — infer from last commit message
```bash
git log -1 --pretty=format:'%s'
```

Map the conventional commit type prefix to a bump level:

| Commit type prefix | Bump level |
|--------------------|------------|
| `feat` | `minor` |
| `fix`, `patch`, `refactor`, `chore`, `docs`, `doc`, `style`, `test`, `perf`, `ci` | `patch` |
| Explicitly mentions breaking change or `major` | `major` |

When in doubt, default to `patch`.

## Workflow

### Step 1: Read Current Version
```bash
grep '^version' Cargo.toml | head -1
```

### Step 2: Determine Bump Level
Apply the decision logic above. Show the user:
- Current version
- Last commit subject (when auto-detecting)
- Proposed bump level and resulting new version

Example output:
```
Current version : 0.3.1
Last commit     : feat(scene): add DeepWater tile type
Bump level      : minor
New version     : 0.4.0
```

### Step 3: Confirm with User
**Always ask for confirmation before running `cargo bump`.**

Present the exact command that will be run:
```
cargo bump minor --git-tag
```

Wait for explicit approval. If the user declines, offer to adjust the bump level instead.

### Step 4: Run (after approval)
```bash
cargo bump <level> --git-tag
```

Then verify the build is still clean:
```bash
cargo check -q
```

Report any errors. If the build is clean, check for lockfile changes:
```bash
git status --short
```

If `Cargo.lock` appears in the output, stage it and amend the version bump commit
(this is intentional — the lockfile is part of the version bump, not a separate change):
```bash
git add Cargo.lock
git commit --amend --no-edit
```

Report the new version and the git tag that was created.

## Examples

```
cargo-bump              → auto-detects bump level from last commit
cargo-bump minor        → force minor bump
cargo-bump 1.0.0        → set exact version
```

## Constraints
- ALWAYS confirm with the user before running `cargo bump`.
- NEVER bump if the working tree has uncommitted changes unrelated to a version bump
  — report the situation and ask how to proceed.
- The `--amend` in Step 4 is the only permitted use of amend; do not amend any other commits.