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

The annotations already cover the safety profile (readOnlyHint, idempotent, non-destructive, closed-world), but the description goes further by disclosing the exact response contents and two conditional edge behaviors: clientCount is null unless partner-scoped, and scopeHint appears only when the credential is not partner-scoped. That conditional return behavior is genuinely non-obvious. It stops short of 5 only because nothing is said about error states or what an unauthenticated credential yields.

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 core identity statement and the 'use this first' instruction are front-loaded, and the sentences carry useful information rather than filler. The parenthetical about clientCount semantics is dense but earns its place given there is no output schema; the description is slightly longer than strictly necessary but not padded.

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 no output schema and no parameters, the description carries the full burden of explaining what comes back, and it does so field by field, including the partner-specific extras and their null conditions. An agent has everything needed to call it and interpret the result.

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?

The tool takes zero parameters, so there is nothing to disambiguate and the baseline of 4 applies. The description does not need to and does not discuss inputs.

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 uses a precise verb ('Identify') plus the exact resource ('the account this credential acts as on Blawgy') and enumerates the concrete return fields: email, role, credential kind, access level, scope, and site count. No sibling tool in the list does this, so an agent can separate it from tools like get_settings or list_team without opening a 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 explicitly states the workflow position ('Call this first in a session') and names the exact next step and alternative ('then list_sites to pick a site'). That gives the agent both a when-to-use and a routing decision, which is rare and highly actionable.

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