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

No annotations are supplied, so the description carries the load. It does disclose the return shape ('full decoded record') and the uniqueness semantics, but it says nothing about what happens when the id is not found, when state is omitted and matches collide, or whether the call is read-only (implied but not stated).

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?

Three short sentences, front-loaded with the identity and lookup key, then the disambiguation rule, then the return value. No filler and nothing redundant.

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 two-parameter read lookup with no output schema, this is nearly sufficient: it names the key, the disambiguator, and the return payload. Only failure/ambiguity behavior is left implicit.

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 baseline is 3, but the description adds genuine meaning: id is an FHWA Item 8 structure number and state disambiguates because uniqueness is per-state. That rationale is not present in the schema text.

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?

Specific verb (get) plus resource (one bridge) plus the exact identifier (FHWA structure number, Item 8). This clearly separates it from the list/search siblings, which return sets rather than a single decoded record.

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?

Explains that structure numbers are unique only within a state and that passing state makes the lookup exact, which tells the agent how to use the optional parameter correctly. It stops short of naming an alternative tool for fuzzy or name-based lookups (e.g. search_bridges), which is the remaining gap.

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