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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent write with open-world scope, so the safety profile is covered. The description adds nothing beyond that: it does not say what happens on a duplicate name (relevant given idempotentHint=false), whether the tag is immediately usable on contacts, or whether a dry-run preview is meaningful — the dry_run parameter's purpose is only explained in the schema.

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?

A single, front-loaded sentence with zero filler or redundancy. It is efficient, though the brevity comes at the cost of any usage or behavioral detail.

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 simple two-parameter create tool with a fully documented schema and helpful annotations, the description is minimally adequate — no output schema exists, so it needn't explain return values. However, it omits duplicate-name behavior and any post-creation workflow, which are the main unknowns for this operation.

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 100%, with both `name` and `dry_run` documented in the schema itself. The description adds no constraint, format, or uniqueness detail beyond that, so the baseline 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?

The description states a specific verb and resource ("Create a new tag") plus the domain purpose ("for organizing contacts"), which is clearer than a bare restatement of the name. It does not distinguish itself from sibling creation tools like create_list or create_segment, which an agent must infer from the resource name alone.

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 create a tag versus a list, segment, or custom field, and no mention of prerequisites or how to associate the tag with contacts afterward. The agent is left to infer everything about selection from the tool name.

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