Query River Mile Markers by River and Mile Range

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, so the safety profile is clear. The description adds useful behavioral details: results are ordered by MILE ascending, paginated via offset with total_count and next_offset, and a 'where' field is included for transparency. It also documents three specific error responses. Minor gap: no mention of rate limits or data staleness, but overall strong for a read-only query tool.

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 well-structured with clear sections: purpose, usage examples, pagination semantics, output format, and error responses. Every line is informative, and the examples are front-loaded. At about 20 lines, it's appropriately sized without redundancy.

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?

Given the tool has 5 parameters with 100% schema coverage, an output schema that documents the return structure, and clear annotations, the description is complete. It covers pagination behavior, error handling, filter constraints, and response structure. No gaps remain for effective agent decision-making.

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 baseline is 3. The description adds value by showing example values (e.g., 'RED', 'MISSISSIPPI', 'OHIO') for river_name, clarifying inclusive bounds for mile_min/mile_max, and demonstrating usage patterns (e.g., 'mile_min=900'). It also explains the interplay between filters ('provide at least one filter'). However, it doesn't add new parameter semantics beyond what the schema already provides, so a 4 is appropriate.

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 queries USACE river mile markers by river name and/or mile-value range, using specific verbs like 'Query' and 'List'. It distinguishes from siblings by mentioning filtering by river and mile range, while sibling names like 'find_markers' and 'nearest' imply different use cases.

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 explicitly states when to use the tool with example queries ('List markers on the RED river', 'How many markers on the Mississippi between mile 400 and 600?') and provides a clear alternative pattern (mile_min=900). It does not mention siblings directly but implies when to use this vs other tools by its focus on combined river and mile filtering.

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