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

Annotations already cover read-only, idempotence, and non-destructive safety. The description adds meaningful behavior beyond that: returns top-N passages with character offsets and similarity scores, uses BGE-base-en embeddings with cosine similarity over 500-char overlapping windows, and has a 200K char cap with truncation flagging. This enriches the agent's understanding of mechanics and edge cases.

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 front-loaded with purpose and then efficiently covers usage, alternatives, technical details, and constraints. Every sentence contributes to the agent's decision-making—no filler or redundancy. It is appropriately sized for the tool's complexity.

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?

Despite lacking an output schema, the description fully covers what the tool returns (passages, offsets, similarity scores), the exact use case, the integration with a sibling, and the input length limit with truncation behavior. For a search tool with 3 parameters, this is complete and self-sufficient.

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%, so the baseline is 3. The description adds value by connecting the limit parameter to 'top-N passages' and giving concrete examples for the query parameter (e.g., 'supply-chain risk', 'fiscal year 2024 revenue'). This contextualizes parameter usage beyond the schema's declarative descriptions, though not significantly beyond them.

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 specific verb and resource: 'Semantic search INSIDE a fetched record.' It clearly distinguishes this from siblings by contrasting with ask_pipeworx_grounded, stating 'Pairs with ask_pipeworx_grounded: fetch with the gateway, ground over the relevant passages instead of the whole document.' This uniquely positions search_within as a text-internal search tool.

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 explicitly states when to use it: 'Use when the record is too big to cram into the prompt.' It also names the complementary alternative (ask_pipeworx_grounded) and explains the workflow: fetch with the gateway, ground over relevant passages. This provides clear context and pairwise guidance with a sibling tool.

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