Read a passage

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds genuinely useful behavior beyond that: the failure conditions ('fails if the ID is unknown or its source was removed') and the returned shape { passage, before, after }. It stops short of discussing pagination or size limits, but that is minor here.

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?

Front-loaded with the core action and ID requirement, then usage, then return shape and failure modes. Dense but every sentence carries information; the only slight cost is that the neighbors detail is repeated from the schema, which costs a clause rather than a sentence.

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?

No output schema exists, yet the description supplies the return structure and citation_url detail, plus failure conditions and neighbor semantics. For a simple two-parameter read tool with full annotation coverage, an agent has everything needed to call it correctly.

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% and both parameters are documented in the schema, including the neighbors 0-3 range, same-page scope, and document order. The description's neighbors sentence largely restates the schema, so it adds little beyond the baseline when the schema does the heavy lifting.

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 ('Reads one passage in full by its ID') and immediately scopes it to post-search retrieval, distinguishing it from the sibling search tool. An agent can tell what it does 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?

Gives explicit when-to-use ('when a search result was shortened, or when you need the text around a passage'), names the alternative ('To find passages, use search instead'), and states the precondition that it follows a search. Nothing is left to inference.

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