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

Annotations only declare readOnlyHint=true, so the description carries most of the behavioral load and does it well: it discloses the public/no-API-key auth model and explains that revoked, suspended, expired and unknown handles all collapse into the same not_found response. That is real added context beyond the annotation, though it says nothing about rate limits or token lifetime/expiry semantics.

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?

Purpose comes first, then the rotation use case, then the auth model and error behavior — a logical front-loaded order with no filler. The em-dash clause makes the opening sentence a little dense, but every sentence contributes information.

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?

With an output schema present and a single fully-described parameter, the remaining burdens are auth requirements, error behavior and purpose, all of which are covered. Nothing an agent needs to call this correctly is missing.

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% and the handle parameter is already documented with its ph_dlg_<32 hex> pattern, so the baseline is 3. The description reinforces the public-handle semantics and adds that any non-active handle yields not_found, which is useful behavior tied to the parameter but not a new format or syntax detail.

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+resource ('Get the current token of an active delegation') and scopes it to the public ph_dlg_* handle, which separates it from the metadata-oriented get_delegation and the verify_delegation siblings. An agent can tell what it returns (a token, not delegation metadata) without inspecting the schema.

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?

It names the concrete triggering situation — after a signing-key rotation, to obtain the re-signed token to publish in place of the old one — which is genuine when-to-use guidance. It does not explicitly name get_delegation as the alternative for non-token reads, so it falls short of full sibling routing.

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