m03-mutability skillA
m03-mutability is agent-read markdown (skill) from moeru-ai/auv: CRITICAL: Use for mutability issues. Triggers: E0596, E0499, E0502, cannot borrow as mutable, already borrowed as immutable, mut, &mut, interior mutability, Cell, RefCell, Mutex, RwLock, 可变性, 内部可变性, 借用冲突.
Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.
What the file says
# Mutability > **Layer 1: Language Mechanics** ## Core Question **Why does this data need to change, and who can change it?** Before adding interior mutability, understand: - Is mutation essential or accidental complexity? - Who should control mutation? - Is the mutation pattern safe? --- ## Error → Design Question | Error | Don't Just Say | Ask Instead | |-------|----------------|-------------| | E0596 | "Add mut" | Should this really be mutable? | | E0499 | "Split borrows" | Is the data structure right? | | E0502 | "Separate scopes" | Why do we need both borrows? | | RefCell panic | "Use try_borrow" | Is runtime check appropriate? | --- ## Thinking Prompt Before adding mutability: 1. **Is mutation necessary?** - Maybe transform → return new value - Maybe builder → construct immutably 2. **Who controls mutation?** - External caller → `&mut T` - Internal logic → interior mutability - Concurrent access → synchronized mutability 3. **What's the thread context?** - Single-thread → Cell/RefCell - Multi-thread → Mutex/RwLock/Atomic --- ## Trace Up ↑ When mutability conflicts persist: ``` E0499/E0502 (borrow conflicts) …
Read the whole file at its exact version.
How to install
mdr add moeru-ai/auv/m03-mutability@git:20260725.8a8e541mdr add moeru-ai/auv/m03-mutability@sha256:1e2d270dbfd28412Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.
[](https://markdownregistry.com/a/art_26j64zwx6iuonmqq)
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Versions
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (4157 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
moeru-ai/auv · 51 stars · license Apache-2.0 · pushed 2026-09-24 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_26j64zwx6iuonmqq GET https://markdownregistry.com/api/v1/resolve?ref=moeru-ai/auv/m03-mutability GET https://markdownregistry.com/api/v1/blob/1e2d270dbfd2841238783bcfed109fbf6b67e4132d698a4a015232a217078c23
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