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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=false, so the safety profile is covered. The description usefully adds that expectedSpecVersion exists to prevent stale writes, implying optimistic-concurrency semantics, but says nothing about permissions, what the duplication copies (styles, filters) or reversibility of a non-idempotent mutation.

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 tight sentences with the purpose front-loaded and the parameter caveat second; nothing is padded. 'Preserving canonical GMS validity' is domain jargon that may not translate for an unfamiliar agent, which keeps it just short of ideal.

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 mutation with no output schema, the description never indicates what comes back (e.g., the new layer's identifier) or what scope of configuration is duplicated, which is exactly the information a caller cannot get from structured fields. The concurrency note is a genuine addition but the definition remains only minimally complete.

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 description coverage is 0%, and the description only compensates for expectedSpecVersion, explaining its stale-write-prevention role rather than restating its minimum/maximum. projectId and the nested input object carry UUID constraints and field descriptions but no explanation of why the layerId/title pair is needed, leaving the burden only partly met.

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 ('Duplicate a map layer') that maps cleanly onto the tool name, so the core action is unambiguous. It does not, however, distinguish itself from adjacent creation tools like geobble_project_add_layer or geobble_studio_add_layer, which an agent could plausibly confuse when a new layer is the goal.

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?

There is no when-to-use / when-not-to-use guidance and no naming of alternatives among the many layer-mutating siblings. The only conditional statement ('expectedSpecVersion is required') describes a parameter obligation, not a usage scenario.

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