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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, establishing a non-mutating, idempotent operation. The description adds valuable context: 'Advisory only' confirms it does not enforce changes, and it discloses authentication requirements (X-Vibes-Key or x402) with a cost estimate (~$0.02) and a potential payment_required response. These are behavioral details beyond annotations, though not extensive.

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 (4 lines) and front-loaded with the core purpose. Every sentence adds value: it states the detection goal, lists flags, names the sibling, and conveys auth/advisory info. No filler or redundancy. It is well-structured for quick parsing.

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 advisory tool with a nested object parameter and an output schema, the description covers the essential usage context: when to use, what it returns (JSON risk assessment or payment_required), and authentication. It does not delve into error handling beyond payment_required, but that is peripheral given the output schema and annotations. Slight gap on any rate-limit or timeout behavior, but overall 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 description coverage is 100%, with each parameter having a clear description in the schema (e.g., retry_config described as 'Retry policy object (attempts, backoff, jitter, concurrency)', fanout as 'Optional parallel callers/workers sharing this policy'). The description does not add new parameter-level detail beyond what the schema provides; it only references retry_config content conceptually (e.g., 'missing jitter') without enriching parameter syntax or constraints. Baseline of 3 is appropriate given the schema's completeness.

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 clearly states the tool's purpose: 'Detect retry configs that amplify load instead of adding resilience.' It specifies the exact scenarios it flags (synchronized backoff, missing jitter, runaway fanout) and explicitly names the sibling tool vc_idempotency_guard, making differentiation immediate. This is a specific verb+resource with clear scope.

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 explicit when-to-use guidance: 'before you enable aggressive retries on paid or rate-limited APIs.' It also names an alternative tool (vc_idempotency_guard) and states what that alternative handles (duplicate side effects), providing clear exclusion criteria. This is direct and actionable.

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