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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds behavioral context by explaining the fallback logic ('profile matching (same strength + origin, comparable rating)'), which clarifies how results are generated. This goes beyond the annotation without contradicting it.

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 tightly written in two sentences. The main purpose is front-loaded, and the addition of algorithm details is relevant without excess. Every sentence contributes value.

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 read-only tool with an output schema present, the description adequately covers the purpose and method. It does not explain return format, but that is handled by the output schema. A slight gap is that it doesn't mention any constraints (e.g., what happens if no similar lines are found), but overall it is 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 0%, so the description must clarify parameters. It does clarify that 'name' refers to the 'given line' (by saying 'a given line'), but it does not mention the 'limit' parameter or its meaning (though it has a default of 8, its purpose is not explained). This is partial compensation, hence a 3.

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 the tool finds 'Cigar lines similar to a given line', which is a specific resource (cigar lines) and action (find similar). It is clearly distinct from siblings like search_cigars (generic search) and get_cigar_line (specific line retrieval), and the title reinforces this.

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 gives an explicit use case: 'for "if you like X, try Y"'. This tells the agent when to trigger it. However, it does not mention when not to use it or explicitly point to alternatives, so it stops short of a 5.

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