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

The description asserts 'Tagging the same label twice is idempotent — no error, no duplicate entry,' but the annotation explicitly declares idempotentHint=false. This directly contradicts the structured metadata and could cause an agent to make a wrong assumption about repeat-call behavior.

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, front-loaded with the core action and effect, with no filler. The only weakness is the final sentence, which introduces the contradiction rather than useful clarity.

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 tool (readOnlyHint=false) with no output schema, the description adequately covers the write effect and the meta.tags mirroring. However, it omits permission/prerequisite context and the incorrect idempotency claim undercuts completeness.

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 coverage is 67%, above the baseline threshold, and the schema already documents both 'name' and 'rationale'. The description reinforces that 'name' is user-supplied and reveals the meta.tags storage side effect, but says nothing about 'map_id' (undocumented in the schema) or the rationale parameter.

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 (label) and resource (current workspace state) and explains the concrete effect (mirrored into workspace.meta.tags). It is clear what the tool produces, though it does not explicitly distinguish itself from the similarly-named sibling add_annotation, which could cause selection confusion.

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 guidance on when to use this over alternatives like add_annotation, save_workflow, or build_map, nor any stated prerequisites. The idempotency note is behavioral, not a usage rule.

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