web_fetch

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

With no annotations provided, the description carries the full burden and does a good job: it discloses anti-crawler interception detection, truthful reporting, and the truncation strategy of keeping head/tail while omitting the middle when max_tokens is exceeded. This goes beyond what the schema alone would tell an agent.

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, front-loaded with the main purpose, and uses a clear bulleted Args section. Every sentence adds useful information without redundancy or filler.

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?

An output schema exists, so return-value shape does not need to be described. The description covers the operation, URL requirement, token budget behavior, link policy variants, and an important edge case (anti-crawling pages). It is slightly incomplete only in not addressing relationship to sibling tools such as web_batch and login.

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 0%, so the description fully compensates by explaining the URL protocol requirement, the max_tokens truncation behavior, and every link_policy option with its default and trade-off. This gives an agent actionable parameter-level semantics that the raw schema lacks.

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 clear verb and resource: it fetches a web page and returns a token-efficient compact body. It also signals a distinctive behavior (auto-detecting anti-crawling block pages), which helps distinguish it from generic fetch tools, though it does not explicitly contrast with its siblings.

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 explains what the tool does and how parameters work, but gives no guidance on when to prefer web_fetch over web_batch or login, nor any conditions where it should not be used. Usage context is only implied by the tool name and the single-page nature of the description.

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