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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, so the safety profile is covered. The description adds genuinely non-obvious behavior: expectedSpecVersion gates against stale writes, i.e. optimistic concurrency control, which is not derivable from the schema. It does not explain what happens when only one of light/dark is supplied or whether omission clears a basemap.

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?

Two sentences, both front-loaded: the action first, the critical constraint second. No filler or restatement of the tool name.

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 three-parameter mutation with a nested input object, zero schema description coverage, and no output schema, the description is too thin. It omits the conflict/retry behavior on stale expectedSpecVersion, whether both basemaps are required, and how to source valid basemap IDs.

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 0% at the top level, so the description must carry the burden — and it only covers expectedSpecVersion and the light/dark distinction. projectId is entirely unexplained, and the nested input.title ('Short description of the basemap change') semantics are left to the schema alone. The partial coverage does not compensate for the gap.

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 (assign) and resource (light/dark basemaps on a project map), which an agent can distinguish from the read-only sibling geobble_project_list_basemaps. It stops short of explicitly differentiating from other project_* mutation tools, but the purpose is unambiguous.

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 when-to-use or when-not guidance, and no alternatives named (e.g., whether geobble_project_list_basemaps should be consulted first to obtain valid basemap IDs). The expectedSpecVersion sentence implies a prerequisite but never states how to obtain the value or what to do on a conflict.

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