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

With no annotations provided, the description carries the full behavioral burden. It discloses the comparison structure (side-by-side, leader flagged per dimension) and scope (all sixteen dimensions). However, it doesn't describe return format, how ties are handled, whether the output is tabular or narrative, or any ordering behavior. For a read-only comparison tool, this is adequate but could disclose more about the output structure.

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?

A single sentence that efficiently conveys the tool's purpose, scope (2-4 metros), granularity (all sixteen dimensions), and the leader-flagging behavior. Zero waste, front-loaded with the main action.

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?

The tool has one parameter (fully documented in schema), no annotations, no output schema, and no nested objects. The description covers the core behavior well. However, since there's no output schema and no annotations, the description could disclose more about the output format (how the leader flag is presented, what fields appear in each comparison row) to fully compensate. It's functional but leaves some ambiguity about the result structure.

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 single 'slugs' parameter is fully documented with minItems 2 and maxItems 4 constraints in the schema. The description's 'two to 4 metros' and 'sixteen scoring dimensions' adds a little context but doesn't go beyond what the schema already conveys about constraints. Baseline 3 is appropriate when the schema does the heavy lifting for a single well-documented parameter.

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 clearly states the tool performs a side-by-side comparison of 2-4 metros across all sixteen scoring dimensions, flagging the leader in each. The verb 'compare' plus the resource scope ('metros') is specific. However, it doesn't explicitly distinguish from the sibling tools like get_metro (single metro details) or list_top_metros (ranking), though the comparison nature is fairly distinct by name.

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 conveys the tool takes 2-4 metros for comparison, which implies it's used when a comparative view is desired. However, there's no explicit guidance on when to use this vs alternatives (e.g., when to use search_metros first to find slugs, or when get_metro would suffice for a single metro). The 'across all sixteen scoring dimensions' adds some context but no explicit exclusions or alternatives are named.

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