Fetch original HTML or text from a public URL with character limits, validating redirects and DNS to provide bounded, traceable evidence for web research.
Extract bounded original HTML/text evidence from a public URL; redirects and DNS are validated.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | ||
| max_chars | No |
Changes observed during successful MCP inspections.
v0.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds real value beyond that: output is bounded/truncated, redirects are followed but validated, and DNS is validated (an SSRF-style safeguard). It does not say what happens on truncation or on fetch failure.
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?
A single dense sentence with zero filler, front-loading the action and the scope (public URL) followed by the validation guarantees. Nothing is redundant with the name or annotations.
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 two-parameter read tool with rich annotations and no output schema, the description covers the important behavioral facts (bounded output, redirect/DNS validation, public-only scope). It is slightly thin on return shape (verbatim HTML vs extracted text) and on what a truncated response looks like.
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% for both parameters, so the description must carry the load. 'Bounded' gestures at max_chars but never names it, states its units, or explains the 12000 default, and the expected URL format is left to the schema type alone.
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 ('Extract') and resource ('original HTML/text evidence') scoped to public URLs, which is more precise than a generic 'fetch'. It does not explicitly differentiate itself from the sibling fetch_pages (plural) or broad_search, so the agent must infer that this is the single-URL variant.
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 'public URL' constraint gives a hint about applicability, but there is no statement of when to use this versus fetch_pages (batch) or broad_search. No exclusions, prerequisites, or alternative routing are given.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.