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

Annotations only carry default false hints, so the description carries the burden and largely delivers. It discloses that the tool 'Creates a record and a mail,' states the return JSON shape (sent, contact), and notes 'No key needed.' This goes beyond annotations with real side-effect and auth context. It stops short of mentioning idempotency or repeat-submission behavior, but that is a minor gap.

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?

The description is a single dense block, but every clause carries weight: purpose, content constraints, usage trigger, exclusions, return format, side effects, and auth. It is front-loaded with the core action. Slightly long, but efficient and well-ordered for an agent scanning it quickly.

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 2-param tool with no output schema and generic annotations, the description is complete. It covers what it does, when to use it, when not to, return structure, side effects, and authentication. Nothing an agent needs to invoke 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 coverage is 100% with both email and items described, so baseline is 3. The description adds meaningful context for items by enumerating example content (chains, SLAs, compliance, features, prices) and the max 1000 chars limit, which the schema's 'free text' does not convey. This extra guidance justifies a 4.

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: 'Send FlexYield an enterprise wishlist.' It clarifies the content (chains, SLAs, compliance, features, prices) and distinguishes itself from siblings by naming manage_tickets and manage_feedback as alternatives for different scenarios. An agent can determine what this tool does even without reading the schema.

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 provides the trigger condition: 'Use it when the public plans do not fit and a human wants to talk.' It also gives clear exclusions with named alternatives for bugs/account questions (manage_tickets) and signed-in product ideas (manage_feedback), leaving no ambiguity about when this tool is appropriate.

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