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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=false; the description usefully adds that results are persisted as derived output rather than computed transiently. It does not disclose whether repeated runs create duplicate layers (relevant given idempotentHint=false), whether the operation is synchronous or job-based, or what permissions/state the project must be in.

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 front-loaded sentence with no filler. The parenthetical operation list is the only questionable content: it partly duplicates the schema enum and is inaccurate, so it does not fully earn its place.

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 mutating, nested-parameter, non-idempotent operation with no output schema, the description omits what is returned (derived layer ID? job handle?), whether execution is async, and how the operation enum interacts with single- vs multi-layer sources. The agent would need the schema plus guesswork to call this correctly.

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?

The description says nothing about parameters, and its operation list conflicts with the enum, so it adds no meaning beyond the schema (which itself does document operation, sourceId, secondarySourceId and the params sub-fields). It never explains which operations require distanceMeters, keyA/keyB, or groupBy, and with schema coverage reported at 0% the description fails to compensate.

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 ('Run') and resource ('predefined spatial operation') and enumerates example operations, so the agent can distinguish it from siblings like project_inspect_source or project_analyze_mobility. However, the parenthetical list ('union', 'proximity', 'spatial join') does not match the schema enum (bounds, buffer, centroid, dissolve, clip, countPoints, intersect, join, subtract), which weakens the otherwise clear statement of purpose.

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?

No guidance on when to choose this tool over the many project_* siblings (e.g., project_analyze_mobility, project_query_database, project_add_layer), and no prerequisites such as the project needing existing sources. The phrase 'predefined spatial operation' hints at a fixed catalog, but the agent must open the schema to learn the actual conditions.

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