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

The description adds substantial behavioral detail beyond the readOnlyHint and destructiveHint annotations: it discloses the live-server behavior, the no-credentials fallback, and the project_group/runtime grouping semantics. It also reinforces the read-only nature by noting the token 'CANNOT delete it.' No contradiction with the annotations is present.

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 purpose is front-loaded, and each sentence contributes relevant information about live data, credentials, account/project selection, or output grouping. It is dense rather than strictly concise, but it avoids filler and is appropriately sized for the tool's complexity.

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?

The description covers the critical invocation decisions: credential requirements, fallback behavior, project selection, and project_group grouping. With only 5 parameters and no output schema, this is reasonably complete, and the remaining parameter details—such as the screen filter and limit—are already captured in the schema descriptions.

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 high at 80%, so the baseline is 3. The description adds extra meaning around the project parameter by explaining how project selection works with and without account_token, and how project_group groups runtime variants. This goes beyond the raw schema descriptions and helps the agent choose correct parameter combinations.

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 first sentence clearly identifies what the tool returns: 'The most recent per-screen performance samples, newest first.' This is specific enough to convey the core purpose. However, it does not explicitly contrast with sibling tools like boosthis_trend or boosthis_snapshot, so the agent must infer when this is the intended tool.

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 gives useful operational context, such as answering live only when read credentials are configured and falling back to a note pointing at the dashboard otherwise. It also explains project selection with and without account_token. But it never states when to prefer this tool over alternatives or when not to use it, so usage guidance is mostly implied rather than explicit.

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