telys_search_lexical

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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds valuable behavioral context beyond that: the dependency on collection creation with lexical=True, the need for telys_build_lexical to have run, and the exact failure modes when the collection or index is missing. This meaningfully fills gaps that annotations do not cover.

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?

The description is compact and front-loaded: the core behavior and key differentiator appear first, followed by prerequisites, parameters, and failure conditions. Every sentence earns its place; there is no filler or redundancy with the schema.

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 search tool with five parameters and no output schema, the description covers the essential operational context: purpose, prerequisites, failure modes, and parameter semantics. It does not describe the return shape or pagination, but for a keyword search this is a modest gap given the annotations already convey safety.

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 only 20%, so the description carries the load. It explains the required collection and query, assigns meanings to optional top_k and explain (including 'per-hit score explanations'), and reinforces the where parameter's single-key equality filter. It adds useful semantic detail beyond the bare schema, though it does not describe value formats or constraints for collection/query.

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 states a specific verb and resource: on-device BM25 lexical search. It explicitly contrasts with fuzzy semantic search, and the detail about exact-term matching for identifiers and rare tokens helps distinguish it from the sibling telys_search. It also names the required prerequisites, making the tool's role unambiguous.

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 clear context on when to use lexical search (exact-term matching where semantic search is fuzzy) and lists the hard prerequisites (lexical=True and telys_build_lexical must have run). It does not explicitly name the alternative sibling telys_search, but the semantic-vs-lexical contrast provides sufficient usage guidance.

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