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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), and the description layers on genuinely non-derivable behavior: cross-lingual matching, ephemeral chunkRef invalidated on item edit, retry semantics for weak results, and the meaning of rerankApplied/vectorSearchApplied degradation flags. This is operational context an agent cannot get from 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?

Purpose and primary triggers are front-loaded, and there is little filler. It is on the long side, and the multi-sentence degradation-flag passage is dense, but every sentence carries distinct operational information rather than restating 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 6-parameter toolkit search with an output schema, the description supplies everything an agent needs: when to use it, sibling routing, retry strategy, and the semantics of fields it will encounter in the response. Return-value detail is not required since an output schema exists.

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 67%, and the description adds real meaning beyond it for the query parameter (queries may be Chinese, English, or mixed; matching is cross-lingual) plus explains how chunkRef maps onto get_item's chunk parameter. It does not clarify tags, provenance, or start/end beyond the schema, so it falls short of a 5.

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 (search) and resource (personal Sensefold library), enumerates the content types indexed, and makes the scope explicit ('by meaning and keywords'). It is clearly distinguishable from list_items (recency browsing) and get_item (full text), both named in the text.

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 triggers ('what did I save about X'), names the alternatives and their selecting conditions (list_items for recency/dates, get_item for full text), and prescribes recovery behavior for empty/weak results and for each degradation flag. 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.