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

Annotations already cover read-only, non-destructive, idempotent, and closed-world behavior. The description adds valuable context: it returns a link and names the tools for checking drafts, and it clarifies that it does not generate email copy itself. This is useful beyond annotations, though no auth or rate-limit details are needed.

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?

Two sentences, front-loaded with the core action. No wasted words—each sentence adds distinct value by stating the external resource and the supported checking tools.

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?

Given the tool has no parameters, rich annotations, and no output schema, the description is complete. It explains what the tool does, its limitations, and what the result contains (the link and relevant checking tools), giving an agent everything needed to decide to call it.

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?

The tool has zero parameters. The schema is empty with 100% coverage, so there is nothing to document. A baseline of 4 is appropriate for a parameterless tool.

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 ('Directs') and resource ('Cold Email AI'), and explicitly clarifies that it does not generate copy. It distinguishes itself from the named sibling tools that check drafts (analyze_cold_email, preview_inbox, expand_spintax), so an agent can immediately understand its role.

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?

It implies when to use the tool by contrasting it with the draft-checking tools, but does not give a direct 'use this when...' instruction. The context is clear enough for an agent to infer that this is for writing assistance, while the listed siblings are for checking drafts.

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