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

Adds substantive traits beyond the annotations: UPSERT-by-asset_id semantics, the global one-placement-per-asset constraint ('calling this again just moves the pin'), and the required asset_placements:write scope. The 'calling this again just moves the pin' line sits in mild tension with idempotentHint=false, but no hard safety contradiction exists, and the mutation/scope disclosure is genuinely useful.

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?

Three sentences, each earning its place: purpose/coordinates, the critical upsert constraint, then the sibling alternative and scope. Front-loaded with the core action and no filler.

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 no-output-schema mutation with annotations already covering the safety profile, the description supplies the essentials an agent needs (coordinates, upsert, uniqueness, scope, bulk alternative). It stops short of describing response/error behavior, but nothing critical to correct invocation is missing.

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%, and the description's only coordinate detail (normalized 0-1, origin top-left) is already documented on the x/y schema properties. It adds negligible meaning beyond the schema, so the baseline of 3 applies.

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 and resource ('Place an asset on a floorplan') plus the coordinate system, and explicitly differentiates from the sibling bulk_create by naming the multi-place path. An agent can pick this over bulk_create without opening either 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?

Names the alternative (bulk_create with resource="asset-placements") and the condition that selects it (placing many assets at once). It also states the upsert behavior that governs repeated invocation, so when-to-use and when-to-prefer-the-sibling are both explicit.

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