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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false. Description adds 'Keyless' indicating no authentication needed, and specifies return format (balanced equation, cross-references). This adds some value but does not cover rate limits, pagination, or additional behavioral constraints.

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?

Description is a single sentence that conveys the database, input types, and output. It is front-loaded with key information and avoids unnecessary words. However, it is somewhat dense and could benefit from slight restructuring for readability.

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 no output schema, the description adequately explains the return format (balanced equation, EC and ChEBI cross-references). It covers the main use case and database source. Missing details on pagination or ordering, but overall sufficient for a search tool with good annotations.

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 baseline is 3. The description repeats the same information for the 'query' parameter that is already in the schema description, and does not elaborate on the 'limit' parameter. No additional meaning is provided beyond the schema.

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?

Description clearly specifies verb 'Search' and resource 'Rhea database of biochemical reactions'. It lists input types (compound name, ChEBI id, EC number, keyword) and output (balanced equation, cross-references), distinguishing it from sibling 'get_reaction' which presumably retrieves a single reaction by ID.

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?

Description explains what kinds of queries are supported (compound name, ChEBI id, EC number, keyword), giving examples in the schema. However, it does not explicitly contrast with sibling tools like 'get_reaction' or specify when not to use this tool. Usage context is implied but not exhaustive.

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