fetch_url

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

Description adds SSRF protection, caching, and conditional summarization beyond annotations' readOnly/idempotent hints. No contradictions. More details on error handling would improve, but current info is solid.

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?

Extremely concise: single opening sentence plus a three-line bullet list. No fluff, every sentence adds value. Perfect structure for quick scanning.

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 output schema exists, description doesn't need return details. It covers security (SSRF), caching, and parameter nuances. Missing authentication or error info, but overall adequate for a fetch tool.

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?

With 0% schema description coverage, the description fully explains each parameter: url is the URL, summarize has Ollama condition, max_chars includes default and advice to increase for full pages. Adds significant value beyond 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?

The description clearly states 'Fetch a URL, convert to markdown' with specific verb and resource. It distinguishes from siblings like web_search and academic_lookup by focusing on fetching a single URL rather than searching or academic data.

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 implies usage: fetch a specific URL for markdown conversion. It doesn't explicitly compare to siblings but provides enough context (e.g., Ollama availability for summarization) to guide appropriate use.

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