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

With no annotations, the description carries the full burden and does this well. It discloses that effective_status/is_valid is derived from the underlying control proof, that revoked/suspended/expired domain proofs invalidate the delegation, and that the delegation never outlives its own expires_at. This is meaningful behavioral context beyond the schema.

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 well organized: purpose and return value first, then the derivation rule, then access requirements. Every sentence carries useful information and there is no padding or repetition.

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 one-parameter read tool with no output schema, the description is fully sufficient. It explains what is returned, the meaning of derived fields, the dependency on proof validity, and the authentication prerequisite. No critical missing information prevents correct invocation.

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 description coverage is 100%, and the pattern already documents the two accepted formats. The description reinforces this by mentioning 'Mongo id or ph_dlg_* handle,' but adds no fundamentally new parameter semantics beyond what the schema provides.

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: 'Get one of your delegations by Mongo id or ph_dlg_* handle.' It also clarifies what is returned (publishable token plus effective_status/is_valid), making the tool's role distinct from list or verification siblings.

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 clearly explains the authentication precondition: a Proof account is required, and start_login does NOT open this tool. It does not explicitly name alternatives like list_delegations or verify_delegation, but the single-item retrieval purpose and the exclusion of start_login provide good context.

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