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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior, so the description does not need to repeat safety. It adds value by explaining that results are IDs/summary fields intended for passing to other tools, and by suggesting a pairing with chembl_mechanism. This is contextual behavioral info beyond annotations, though not exhaustive (e.g., no pagination details, but those are in the output 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?

Two tight sentences with zero redundancy. The primary function is front-loaded, output and chaining guidance follow, and the alternative tool is mentioned only once. Every clause earns its place, making it easy to scan and understand quickly.

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?

Given the moderate complexity (3 parameters, 1 required, output schema present) and existing annotations, the description is complete. It explains what the tool does, what results look like, how to use them post-hoc, and mentions a complementary tool. There is no critical missing information an agent would need to call it correctly.

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?

The schema has 100% description coverage for all three parameters (type, limit, query), so the description need not explain them. It does tie the `type` parameter to the entity list ('molecules, targets, assays, or documents'), which slightly reinforces the schema, but adds no new semantic detail beyond what the schema already provides. This matches the baseline for high schema coverage.

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 ('Full-text search'), a specific resource ('ChEMBL drug-discovery database'), and enumerates the entity types searched (molecules, targets, assays, documents). It also names the output (ChEMBL IDs and summary fields) and gives an example of downstream use, making it unambiguous and distinguishable from generic search tools.

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 provides clear context for when to use this tool and how to chain results into `molecule`, `target`, or `activities`. It also explicitly mentions a complementary tool (`chembl_mechanism`) for a different input style. However, it does not explicitly state when NOT to use it (e.g., vs. `search_within`), leaving some inference required. Still, the guidance is strong enough for an agent to route correctly.

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