DeepSeek Web Fetch

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

With readOnlyHint and openWorldHint already declared, the description still earns credit by disclosing the output shape (Markdown of main content), a hard truncation at 30000 chars, and a non-deterministic failure mode ("result availability depends on the target site's access policy"). It doesn't cover things like redirect handling or timeouts on slow sites, but the key behaviors an agent needs are present.

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 sentences, front-loaded with purpose and output format before constraints. Every clause carries operative information; nothing is redundant with the name or title.

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 one-parameter read tool with no output schema, the description covers what it returns, how much of it, what inputs are valid, and why it might fail. Nothing material is missing given the simplicity of the interface.

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 coverage is 100%, so the baseline is 3; the description adds real value by constraining the accepted value to "plain http/https URLs only," which the schema cannot express. It doesn't mention the 8192-char cap, but that is already in 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 and resource ("Fetch a single web page") and immediately characterizes the output ("main content converted to Markdown, truncated at 30000 chars"). This is clearly distinguishable from the sibling deepseek_search, which finds URLs rather than reading them.

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?

Gives an explicit sequencing rule: "Use after deepseek_search to read a specific result URL in full," which routes the agent between the two siblings. It also states two constraints (plain http/https only, access-policy-dependent availability) but stops short of saying when *not* to fetch (e.g., non-article or auth-walled pages should be skipped).

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