Does 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 two things annotations cannot convey: boilerplate stripping behavior and a per-call price ($0.002), which is decision-relevant for an agent. It stops short of disclosing behavior on JS-rendered, paywalled or failed pages, and says nothing about rate limits.

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?

Two sentences, front-loaded with the action and result, then the cleaning guarantee, then cost. Nothing is redundant and nothing needs re-reading.

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 simple two-parameter fetch tool with no output schema and strong annotations, the description covers what it returns, what is stripped, and what it costs — enough to call it correctly. The remaining gap (behavior on dynamic/paywalled content and how truncation surfaces) is minor but real.

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 100%, with both url and max_chars documented (default 20000, range bounds) in the schema itself, so the baseline is 3. The description adds no meaning beyond the schema — notably it does not say whether truncation at max_chars is silent or signalled.

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 web page') plus a specific output form ('return its main content as clean Markdown'), and adds the pre-processing guarantee (nav, ads, scripts, cookie banners removed). No sibling in the list (site_metadata, domain_report, security_headers) returns page body content, so an agent can route here without opening the 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?

The intended use is only implied by 'ready for an LLM to read' — the description never says when to choose this over site_metadata/domain_report or what kinds of pages it does not handle. There are no explicit exclusions and no alternatives named, so usage must be inferred from the purpose.

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