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

Annotations already declare readOnlyHint, idempotentHint and closed-world behavior, so the safety profile needs no restating. The description adds the return shape (slug, name, aliases, summary), which matters because there is no output schema, but it says nothing about ordering, size, or whether the catalog is static.

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 sentence, front-loaded with scope and followed by the fields returned. No filler, no redundant restatement of the title.

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 no-parameter, read-only catalog listing, the description covers purpose and returned fields well enough to call the tool correctly without an output schema. Only minor details, such as result ordering, are absent.

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 takes zero parameters, so the schema imposes no semantic burden and the description has nothing to compensate for. Baseline 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 names the specific resource ('Every vertical Callvu serves') and enumerates exactly what each entry contains (slug, name, aliases, one-line summary). It clearly reads as a full-catalog listing rather than a single lookup, implicitly distinguishing it from get_vertical, though it never names that sibling.

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?

The word 'Every' signals this is the enumeration path for agents that need the complete set rather than one industry, which is a usable implied usage cue. However, there is no explicit when-to-use statement and no mention of get_vertical as the alternative for fetching a single vertical.

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