Fetch

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

The description discloses the critical behavioral trait of browser fingerprint emulation (JA3/JA4, TLS, HTTP/2) to avoid detection. Without annotations, this provides transparency about why requests succeed. However, it does not mention whether the tool is read-only or has side effects, though HTTP fetch is inherently non-destructive to local state.

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 extremely concise: two sentences that front-load the core purpose and differentiator, followed by usage guidance. Every sentence serves a purpose, and there is no 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?

Given the tool has 16 parameters, no annotations, and no output schema, the description is somewhat incomplete. It does not explain what the tool returns (e.g., status code, headers, body format) or that the response is a standard HTTP response. While the schema covers some constraints like maxResponseBytes, the agent lacks clarity on what to expect after invocation.

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 88%, so the input schema already documents most parameters. The description adds general context about the underlying library and fingerprinting motivation but does not provide additional details on individual parameters beyond what schema descriptions offer. The baseline of 3 is appropriate.

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 identifies the tool as an HTTP fetch client with browser fingerprint emulation to bypass bot detection. It specifies the verb 'fetch', the resource (URLs), and the unique value proposition (curl-impersonate style). This distinguishes it from standard HTTP clients and makes its purpose immediately obvious.

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 explicitly states when to use the tool: 'against sites that block or challenge plain scrapers'. It contrasts with Node's default HTTP client, implying an alternative. However, it does not list explicit sibling tools or provide when-not-to-use guidance, such as for sites without bot detection.

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