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

Discloses read-only behavior (matching readOnlyHint) and adds the rate-limited-per-domain constraint beyond the annotations. It doesn't mention error handling, empty result behavior, or log retention, but the key side-effect-free nature is transparent.

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?

Two tight sentences with strong front-loading: the primary action first, followed by usage context and constraints. Every clause adds value.

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 tool with no output schema, the description adequately covers what it does, when to use it, and its constraints. It doesn't describe the return format or log content shape, but given the tool's simple nature and the presence of sibling status/doctor tools, the provided context is sufficient.

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 descriptions for lines (max lines, default 200) and since (minutes back, default 60) are clear, but project_uuid has no description and the tool description adds no parameter clarification beyond the schema. 67% schema coverage sits below the high threshold, leaving a notable gap.

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 (Fetch), a clear resource (Cloud Run logs), and a scoped subject (project's deployed app). The phrase 'THE tool for diagnosing a failed/stalled cloud deploy or a crashing app' strongly distinguishes its intended purpose from sibling build_* tools.

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?

Explicitly states when to use it — for diagnosing failed/stalled deploys or crashing apps — and provides concrete examples (startup-probe timeouts, tracebacks, 'container failed to start on PORT'). It doesn't explicitly name sibling alternatives like build_deploy_status or build_doctor, but the diagnostic framing gives clear when-to-use context.

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