get_delegation_carriers

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

Beyond readOnlyHint=true, the description discloses what is actually inspected (DNS pointer, card fetch), the authorization scope (delegations:read), and that there is no revoked-only restriction. The access block is especially valuable: it states a Proof account and PROOF_API_KEY are required, that a server restart is needed, and that start_login does NOT unlock this tool — a behavior no annotation or schema conveys.

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 tight blocks: capability first, then access prerequisites, so the critical routing information is front-loaded and nothing is padded. The opening sentence is dense and slightly hard to parse on first read (the colon-appended list of checked surfaces), which costs a point.

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?

An output schema exists, so return-value explanation is unnecessary; what remains — what is checked, when it matters, required scope, and the account/API-key prerequisite — is all stated. For a single-parameter read tool, an agent has everything needed to call it or know why it cannot.

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 single `id` parameter already documents "Delegation ID or ph_dlg_* handle"; the description repeats that same fact without adding format, validation, or lookup behavior. With the schema doing the heavy lifting, the baseline 3 applies.

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?

"Report where a delegation is still visible to a third party" states a specific verb (report) and a specific resource (residual delegation visibility), then enumerates the two concrete surfaces checked: the _mcp.<principal> DNS pointer and a direct card fetch for url delegates. It explicitly contrasts with the sibling get_delegation, so the agent can distinguish the two without opening either 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?

"which matters after a revocation" gives a clear triggering condition, and the note about sharing get_delegation's read scope but having "no revoked-only gate" clarifies when this read differs from the plain delegation read. It stops short of an explicit "use get_delegation instead when you only need delegation details" statement, so it is strong context rather than a full when/when-not matrix.

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