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

Annotations declare readOnlyHint=true, and the description adds behavior beyond that: it is a 'hybrid search' and it 'returns labeled passages with links where available.' This gives the agent useful expectations about result shape and source-material behavior without contradicting the annotation.

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 compact sentences, each earning its place: the first defines scope, the second describes output behavior, and the third routes to the correct sibling. The key information is front-loaded.

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 read-only search tool with two fully documented parameters, the description covers scope, output ('labeled passages with links'), and sibling differentiation. No output schema exists, but the description sketches the return value adequately.

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%, so the schema already documents both parameters fully. The description does not add new parameter-level meaning beyond the schema, which aligns with the baseline expectation.

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 names a specific verb ('search') and a distinct resource ('classical text corpora themselves'), and enumerates the corpora (Mishnah, Talmud, Rashi, Rambam, Shulchan Aruch, Tanya, commentaries). It explicitly distinguishes itself from lessons, separating it from the sibling search_lessons even before that sibling is named.

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 gives explicit routing guidance: 'Use search_lessons for our teaching; use this for the primary texts.' This states both when to use this tool and when to prefer an alternative, leaving no inference required.

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