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

Annotations already declare readOnlyHint=false and destructiveHint=false; the description usefully clarifies that the mutations available are tag changes, unsubscribe, and trash (reversible, matching restore_contact / delete_contact_permanently as the permanent path). It does not state partial-failure behavior, whether one bad id aborts the batch, or permission requirements.

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?

One sentence, front-loaded with the scope limitation and then the available actions. No filler or 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 3-parameter mutating tool with no output schema, the description leaves important gaps: the conditional relationship between action and tag, and what happens to the batch when some ids fail. Annotations cover the safety profile, but the operational contract is incomplete.

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 0%, so the description must carry the load, and it only partly does: it restates the 1-200 id range from the schema and names the action families. It never explains that 'tag' is conditionally required for add_tag/remove_tag, nor what each enum value does beyond its literal name.

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 (bulk action) and resource (contacts), plus the scope (1-200) and the three action families (tags, unsubscribe, trash). It does not name a sibling like change_contact_tag or batch_records to differentiate, so it stops short of a 5.

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?

Usage is implied by the scope and action list: use this when acting on many contacts at once. There is no explicit statement of when to prefer change_contact_tag for a single contact, nor any prerequisite or warning guidance.

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