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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds substantial behavioral context: the normalized result structure (position, title, url, snippet, source, domain), the meta envelope (cache state, provider, took_ms), and the provider_required error condition. It does not mention rate limits or pagination, so a 4 is warranted.

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 three sentences, each serving a distinct purpose: stating the core action and provider abstraction, detailing the return envelope, and providing usage guidance. It is front-loaded with the verb and resource, with no fluff or repetition.

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?

Despite no output schema, the description compensates by explicitly listing return fields and the meta envelope. It also covers error handling, provider abstraction, and sibling differentiation. For a 4-parameter tool with robust annotations, this is complete and self-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?

All four parameters are fully described in the schema (100% coverage), so the description need not repeat them. The description adds a minor nuance about the provider parameter ('configured operator-side'), but otherwise relies on the schema. This matches the baseline for high schema coverage.

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 uses a specific verb ('Search the web') and identifies the resource (web via a provider-abstracted backend). It explicitly distinguishes from sibling instant_answer by stating 'Use this for a full web SERP; use instant_answer for quick facts/definitions,' making its scope unambiguous.

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?

Provides explicit guidance on when to use this tool vs. instant_answer, and also notes a critical precondition: a provider_required error occurs if no search provider key is configured upstream. This helps the agent decide and anticipate failures.

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