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

The description goes well beyond annotations: it discloses create-only exclusivity, that only signed writes from owner-listed keys are later accepted, and that claims use either a configured identity or externally supplied did/sig/nonce. The nonce-bound signing semantics are also surfaced. This adds meaningful behavioral detail beyond readOnlyHint=false and idempotentHint=false.

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?

Two dense sentences carry all essential information, with the core action and exclusivity rule front-loaded. Every clause contributes: ownership mechanism, first-claimant behavior, post-claim write policy, and signing modes. There is no filler.

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 mutating tool with no output schema, the description adequately covers claim semantics, exclusivity, and authentication path. It does not describe return/error behavior for an already-claimed room, but the 'first claimant wins' phrasing makes that outcome inferable. Overall, the agent has enough context to invoke the tool 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?

Schema coverage is 100%, so the schema already documents each parameter. The description adds value by explaining the relationship between did, sig, and nonce, and that 'the signature covers the claimant's own did as the value.' This goes beyond the individual parameter descriptions.

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 states a specific verb and resource: 'Claim ownership of a d- room by storing this identity's did:key in room-owners.' It further clarifies the unique semantics with 'create-only: first claimant wins,' which clearly distinguishes it from read/list tools and from set_room_allow.

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 'create-only: first claimant wins' phrasing makes the intended use case clear: claiming an as-yet-unowned room. The second sentence also conveys when to rely on the configured signing identity versus supplying did/sig/nonce externally. However, it does not explicitly name or contrast sibling tools.

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