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

With no annotations provided, the description carries the full burden of behavioral disclosure. It transparently reveals two non-obvious behaviors: the consent prerequisite and idempotency on name collision (returning created=false). It does not detail the success response structure, but for a simple create operation these disclosures are substantial and beyond what the schema alone conveys.

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 with zero waste. The purpose is front-loaded, followed by the two key constraints (consent and idempotency). Every word earns its place, and the structure is optimal for agent scanning.

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 tool with two parameters and no output schema, the description covers the essentials: purpose, consent requirement, and idempotency behavior. It does not explicitly state the success return value (e.g., created=true) or any side effects, but these are reasonably inferred. The description is sufficient for an agent to invoke the tool correctly without missing critical constraints.

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 50% (only 'name' has a description; 'color' does not). The tool description adds no additional parameter information—it does not explain color format, default values, or interactions between parameters. Since coverage is not low (<50%) and the description does not compensate, a baseline of 3 is appropriate.

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 ('Create a tag') and is clearly distinct from sibling search_tags. The idempotency note further clarifies the tool's purpose as a creation operation with collision handling, leaving no ambiguity about what it does.

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?

Explicitly states a critical usage condition: 'ONLY after explicit consent.' This is a clear 'when to use' guideline. However, it does not mention alternatives (e.g., search_tags to check for existing tags) or provide 'when-not' scenarios beyond the consent requirement, so it falls short of a full 5.

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