DeepSeek Web Fetch

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

Annotations already declare readOnlyHint and openWorldHint, so safety and scope are covered structurally. The description adds genuinely useful behavior the agent cannot infer: the return shape (title + Markdown body) and the truncation of long pages, which affects how results should be trusted.

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?

Three short sentences, zero redundancy, with the core capability front-loaded and the usage rule and truncation caveat following in order of importance. Every sentence earns its place.

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 single-parameter, read-only tool with no output schema, the description covers what the agent most needs: the return format and the truncation limit. Nothing required to invoke it correctly is missing.

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?

The single `url` parameter is 100% documented in the schema (absolute http(s), host required, no credentials), so the description is not obligated to compensate. 'One web page' reinforces the single-URL constraint but adds no syntax or format detail beyond the schema.

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 bounded resource (one web page), and the exact return payload (title plus Markdown body). An agent can distinguish this from `search` purely from the description without opening either schema.

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 names the sibling and the condition that selects this tool: 'Use after `search` when a single result needs full-text reading.' It does not state the inverse case (e.g., don't use it to read many documents at once), but the sequencing guidance is clear enough to route correctly.

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