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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds real behavioral context the annotations cannot: the key itself is never returned, and identity is resolved from the MCP transport rather than the call. It also discloses the return shape (yes/no plus linkage timestamps). It does not mention error or unauthenticated-transport behavior, which keeps it from a 5.

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?

Three short sentences, front-loaded with the answer the tool returns, then the privacy guarantee, then usage and the no-parameter note. Every sentence carries distinct information with no padding.

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?

There is no output schema, but the description compensates by describing what is returned (linked yes/no and when it was last linked/rotated) and confirming the key value is never exposed. Combined with the annotations covering the safety profile, an agent has everything needed to call it 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?

Zero parameters, so the baseline is 4, and the description earns that by explaining why there are none — identity comes from the MCP transport, not the call. That preempts an agent trying to pass an account identifier.

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?

States a precise verb+resource (reports whether the authenticated account has an account_api_key linked) plus the extra payload (last linked/rotated timestamps). It is clearly distinguishable from the surrounding get_*/set_* configuration siblings, which deal with pagesets, github, projects, and scaffolds rather than account key state.

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?

Gives an explicit when-to-use: 'check whether key-gated tools will work before calling them.' That is actionable routing guidance. It stops short of naming a specific alternative tool or stating when-not to call it, so it is clear but not exhaustive.

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