List your API key pool

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=true, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: it states the return shape (pooled keys plus legacyKeys metadata), explicitly says 'never the raw secret', and clarifies that legacyKeys are read-only metadata for pre-pooled credentials. This is meaningful additional transparency.

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 compact and front-loaded: it states the core action and grouping first, then the return shape, then the safety note, then usage guidance and the sibling alternative. Every sentence earns its place with no redundancy.

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?

For a read-only list tool with one documented parameter and no output schema, the description is nearly complete. It explains the return structure, the safety property (no raw secrets), and the usage context. The only minor gap is that it doesn't describe pagination or ordering, but for a list of pooled keys this is a small omission given the annotations already cover safety and idempotency.

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 description coverage is 100%, so the schema already documents the single parameter (projectId). The description doesn't add parameter-level detail beyond what the schema provides, but it does clarify the overall return semantics. Baseline 3 is appropriate when the schema carries the parameter documentation burden.

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 states a specific verb ('List'), a clear resource ('the project's BYOK API keys'), and a grouping dimension ('by provider'), naming the exact providers. It also distinguishes itself from siblings by explicitly pointing to add_byok_key as the tool for adding keys, so an agent can tell it apart 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?

The description explicitly says when to use this tool ('Use to see which keys are validated, active, pending, legacy, or rate-limited') and names the alternative for a different action ('use add_byok_key to add one'). This is clear context with an explicit exclusion and alternative.

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