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

The annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the description does not need to repeat safety. It adds value by stating the auth requirement ('Needs your API key') and disclosing the exact return shape for both scopes, which is not in the annotations or output schema. It does not mention pagination or limits, but for a simple read operation this is not a significant gap.

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 description is dense but every sentence earns its place: operation, scopes, use cases, exclusions, output format, auth, and safety. The most important information is front-loaded, and the exclusion clauses are compact rather than verbose.

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 fully specifies the JSON response for both scopes, including field names. It also covers purpose, when to use it, when not to use it, alternatives, auth, and read-only behavior; nothing needed to call it 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%, so the baseline is 3. The description adds meaning beyond the schema by explaining what each scope means ('wallet claims and budgets' for agents) and confirming the default behavior. This helps an agent understand the single parameter's practical effect better than the schema alone.

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 names a specific verb ('List') and resource ('API keys of your account' or 'agent fleet'), and immediately distinguishes the two scopes. It also differentiates from sibling tools like configure_key, revoke_api_key, get_usage, and what_can_i_do, so an agent can select it without opening schemas.

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 says when to use this tool: to find a key id before configure_key or revoke_api_key, or to see which keys are in use. It also gives clear exclusions: not for usage numbers (get_usage) and not for the caller's key standing (what_can_i_do), leaving no ambiguity about alternatives.

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