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

The readOnlyHint annotation already establishes that this is a safe, non-destructive operation. The description adds meaningful behavioral context by specifying the output scale (0 to 1) and the meaning of the endpoints (1 similar, 0 dissimilar). It does not discuss algorithm choice, empty input handling, or performance, but those are less critical for a simple read-only computation.

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 a single, efficient sentence that front-loads the return value and immediately clarifies its interpretation. Every clause earns its place, and there is no unnecessary repetition or padding.

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 simple two-parameter computation tool with full schema coverage and a read-only annotation, the description provides everything an agent needs: the return type, the score range, and the semantic meaning of the range. No output schema exists, but the description itself explains the result adequately.

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 100%, so both text_1 and text_2 are already fully documented in the schema, including the 5000-character limit. The description only refers to 'two given texts' and adds no further parameter guidance, so the baseline score of 3 applies.

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: it returns a similarity score for two given texts. It clearly defines the output range, making the function understandable. However, it does not differentiate itself from sibling text-analysis tools such as analyzeSentiment or spellCheck, so it stops short of full sibling clarity.

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?

There is no guidance on when to use this tool versus alternatives like analyzeSentiment, detectLanguage, or getThesaurus. The description only explains what the tool returns, not the contexts or conditions under which it should be selected.

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