Read a page

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

Annotations already cover safety (readOnlyHint) and world reach (openWorldHint), and the description adds real behavior beyond them: two output modes depending on whether a query is supplied, and truncation to a shared budget in the no-query case. It doesn't discuss failure modes or rate limits, but the URL restriction is already carried by the schema.

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, front-loaded with the precondition, then formats, then the two-mode behavior. No filler and nothing repeated from the schema verbatim.

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?

With an output schema present, return values needn't be described, and the description covers formats, the two extraction modes, and the budget cap. The only thin spot is what happens on refused or unreachable URLs, which is left entirely to the schema's url field.

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 earns an extra point by explaining the conditional semantics of `query` — that supplying one yields answer-bearing passages "the same way search does" — and that omitting it returns main text clipped to a budget. That connects `query` and `max_passages` behaviorally in a way the per-field descriptions do not.

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 ("Read one page") and immediately scopes it to URLs the agent already possesses, which cleanly separates it from the search siblings. It also names the supported content types (HTML or PDF), so an agent knows what it can point this at 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 phrase "whose URL you already have: a link the user pasted, or one from earlier results" tells the agent the precondition for use and implicitly rules out discovery (that's what search/deep_research are for). It stops short of naming a sibling as the alternative for the discovery case, so it's clear context rather than an explicit when/when-not pair.

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