set_river_widths_depths

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

Annotations already declare destructive=true, idempotent=true, readOnly=false, so the safety profile is covered. The description adds genuine context beyond that: a single metadata-sync at the end and read-back of applied arrays, which the annotations do not convey. It stops short of explaining overwrite semantics or what happens on a point_count mismatch.

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?

Front-loaded with the core scope and bulk rationale, then constraints, then applicability. The trailing 'Returns:' block is warranted since no output schema exists. Dense but each clause carries weight; minor redundancy between description and schema on the length constraint.

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 destructive bulk-mutation tool with annotations and no output schema, this covers scope, indexing, length constraints, applicability, and return shape. The main gap is error behavior when array length mismatches point_count, and it never cross-references the per-point sibling.

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 a 3 is the baseline, but the description adds real meaning: the point-i-to-spline-input-key-i indexing mapping and the 'and/or' optionality are not spelled out in the schema. The length constraint itself duplicates the schema's 'length must equal point_count' 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?

States a concrete verb+resource+scope: 'Set a river's width and/or depth at EVERY spline point in one call (bulk taper authoring).' The 'EVERY spline point' framing implicitly separates it from the single-point sibling set_river_width_depth_at_point, so an agent can distinguish them without opening a schema.

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?

'River water bodies only' gives a clear applicability boundary, and 'avoids one MCP round-trip per point' signals the bulk-vs-per-point tradeoff. However, it never names the alternative tool (set_river_width_depth_at_point), leaving the routing inference to the agent.

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