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

Annotations already declare this a non-read-only, non-idempotent mutation, so the safety profile is covered. The description adds genuinely useful behavioral context beyond annotations: expectedSpecVersion exists to prevent stale writes, i.e., optimistic concurrency enforcement. It still doesn't say whether unspecified basemap slots are cleared or preserved, or what permissions are needed.

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 short sentences with zero waste; the core action is front-loaded and the versioning guard follows immediately. Nothing to trim.

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 nested-input mutation tool with no output schema and only generic annotations, the description covers purpose and the concurrency guard but omits what happens to existing basemap assignments, the required title field in the input object, and any error/return expectations. Adequate minimum, with clear gaps.

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?

Top-level schema coverage is 0%: projectId and expectedSpecVersion carry no descriptions. The description compensates for expectedSpecVersion ("required to prevent stale writes") and conveys that light/dark basemaps are optional ("and/or"), but gives no meaning for projectId and doesn't mention the required input.title field. Partial compensation only.

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 states a specific verb ("Assign") and resource ("light and/or dark basemaps to a project map"), which is clearly distinct from the sibling project_list_basemaps. It stops short of naming that sibling or explicitly contrasting read vs. write, so it is clear but not fully sibling-differentiated.

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?

Usage is implied by the verb and the sibling set (project_list_basemaps exists for discovery), and the description adds the prerequisite that expectedSpecVersion is required. However, it never says when to use this vs. alternatives, nor that basemap IDs should be obtained from project_list_basemaps first.

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