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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=true, so the safety profile is covered. The description goes beyond them by specifying the idempotent behavior concretely — a duplicate assignment succeeds as a no-op and returns alreadyAssigned: true — and by stating the access requirement. No error/rate-limit detail, but solid added context for a mutation tool.

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 short sentences, front-loaded with the operation, then the exclusivity rule, then the permission and no-op semantics. Every sentence carries information an agent needs.

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?

With no output schema, the description usefully discloses the alreadyAssigned result field. All three parameters are accounted for, the mutual-exclusion rule and access requirement are stated, and nothing needed to call it correctly 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 mutual-exclusivity of taskId/projectId is already written into the schema property descriptions, so the description mostly restates it. It does reinforce the constraint in prose, but adds no syntax, format, or default information beyond the schema.

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 (tag) plus the two target entity types, so the operation is unambiguous. It does not name the inverse sibling unassign_tag or distinguish itself from create_tag, but the core purpose is fully clear.

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?

Explicit constraints: provide either taskId or projectId but not both, and the caller must have access to the target entity. There is no routing advice to alternatives (e.g., unassign_tag), but the preconditions for correct invocation are stated.

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