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

Beyond the readOnly/idempotent/destructive annotations, the description reveals the hybrid retrieval mechanism (query expansion, embeddings, keyword matching, precision filter) and the expected result presentation (hyperlink post titles to permalinks plus a 1-2 sentence summary). This is useful behavioral context that annotations cannot express, though it is somewhat algorithm-heavy.

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?

Four short sentences with the core purpose front-loaded. Each sentence contributes either selection guidance, behavioral transparency, or output formatting; there is no repetition of schema fields or annotation flags.

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 no output schema, the description covers purpose, when to use it, retrieval behavior, and practical output format (title + Reddit permalink + summary). The main gap is not stating the returned item shape or zero-result behavior explicitly, but the schema and annotations cover the rest.

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 input schema already documents query, limit, and min_similarity fully. The description adds no parameter-level information beyond reinforcing the query style, so the baseline of 3 applies.

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 opens with a concrete verb and resource ('Search saved posts by meaning') and clarifies semantic matching ('even when they use different words'), which distinguishes it from a plain keyword search sibling. The conceptual examples reinforce what the tool is for.

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?

'Best for conceptual queries like ...' gives an explicit trigger condition and examples. It does not name an alternative or say when to prefer exact-match/keyword search, so it stops short of full when-not guidance.

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