Save the repo architecture digest

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly states a critical behavior: 'Overwrites the previous one,' warning about destructiveness. It also describes the side-effect of `covers` — 'lets later sessions be told when a covered file changed' — which adds transparency about how the stored digest is used. This goes beyond a generic 'save' description.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences, front-loaded with the core purpose, and every sentence adds distinct value: purpose, `covers` behavior, and overwrite warning. No unnecessary words or repetition of schema details.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with two params, no output schema, and no annotations, the description covers the essential aspects: what the tool does, what the main parameter content should look like, the role of `covers`, and the overwrite behavior. It doesn't mention return values or error handling, but for a save operation this is minor. The description is sufficiently complete for an AI agent to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Although schema coverage is 100% (each parameter has a description), the tool description adds meaning: it explains the purpose of `covers` ('lets later sessions be told when a covered file changed') and gives content guidance for `text` ('Save the why and the shape, not a symbol list'). This supplements the schema's descriptions with behavioral context.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose with a specific verb and resource: 'Store a compact how this repo works cheat-sheet' — describing modules, flows, entry points, and conventions. It distinguishes itself from siblings like search_symbols by explicitly saying 'Save the why and the shape, not a symbol list,' and from digest_get by implying this is the write counterpart.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context for when to use the tool: 'so future sessions read a page instead of re-exploring' and explains that `covers` enables change detection for later sessions. While it doesn't explicitly name alternative tools or list when-not-to-use scenarios, the introductory phrasing strongly implies its intended use case and content boundaries ('not a symbol list'), which is sufficient for a simple utility.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.