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

No annotations, so the description carries the burden; it discloses the return content (Poor-condition and posted/closed counts per county), which is useful for a tool with no output schema. It does not state read-only safety, ordering, or whether counties with zero bridges are included.

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?

One front-loaded sentence with the resource and returned metrics, zero waste.

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 one-parameter read tool with no output schema, the description names the aggregate unit (per county) and the metrics returned, which is what an agent most needs. Minor gaps: no mention of county coverage or empty-county behavior.

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% with the single 'state' parameter documented and exemplified ('IL'). The description's 'for a state' reinforces scope but adds no syntax or format detail beyond the schema, so the baseline 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?

States a specific verb+resource: per-county bridge counts for a state, including Poor-condition and posted/closed metrics. This is distinguishable from siblings like get_state_summary (statewide rollup) and list_bridges_in_county (per-county listings), though it doesn't name them explicitly.

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?

Usage is implied by 'for a state' – an agent can infer this is the aggregated county-level rollup rather than a raw bridge list. But there is no explicit when-to-use, no exclusion, and no alternative tool named.

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