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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds genuinely new context: it never echoes the key, email, or Stripe session, and it encodes the tier-gating rule that only corpus/corpus-annual/enterprise unlock the full-corpus deliverable. It stops short of describing error or invalid-key behavior, which matters for a verification tool.

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 sentences, front-loaded with the verb and the return contract, with no filler. The return-field enumeration is compact and every sentence earns its place.

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, return shape needs only a summary, which the description provides, along with privacy guarantees, the tier-gating rule, and a usage trigger. Nothing essential for correct invocation is missing for a one-parameter read tool.

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?

Single parameter with 100% schema description coverage, so the schema already carries the semantics including the 'cg_...' format. The description only implies the input is the key under test, which is adequate but adds nothing beyond the schema.

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 specific verb+resource ('Verify an access key') and immediately says what it reports ('what it unlocks'). An agent can distinguish it from read-style siblings like get_access_info, though no sibling is named explicitly to sharpen the boundary.

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 a concrete when-to-use: 'confirm a freshly-purchased key works before relying on it.' It does not address when to prefer get_access_info or get_payment_info instead, so routing guidance is incomplete but the primary trigger is clear.

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