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

Annotations already declare destructiveHint=true and idempotentHint=false, so the safety profile is covered by structured data. The description adds useful effect scope ('stop receiving campaigns and automations'), but omits key behavioral facts for a destructive bulk op: whether it is reversible (a bulk-resubscribe-contacts sibling exists), whether partial failures are possible, and whether transactional mail is unaffected.

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 short sentences, front-loaded with the action and its scope; nothing extraneous. The second sentence partly restates the first but adds clarifying detail about campaigns and automations, so it earns its place without being essential.

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 single-parameter tool with full schema coverage, full annotations, and no output schema, the definition is close to sufficient. The remaining material gap is the reversibility/irreversibility story and any note on bulk partial-failure behavior for a destructive operation.

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% and the schema already documents the con_xxx ID format and the maxItems=100 limit. The description's 'up to 100 contacts' merely restates the maxItems constraint rather than adding new meaning such as behavior on invalid or unknown IDs, so the baseline 3 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 a specific verb (unsubscribe) and resource (contacts) plus scope (up to 100, all marketing email), so the agent knows exactly what the tool does. It does not explicitly name the counterpart sibling tool (bulk-resubscribe-contacts) or differentiate from adjacent tools like bulk-remove-audience-subscribers, which keeps it below 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?

'Unsubscribe from all marketing email' implies the scenario, but there is no explicit when-to-use statement, no exclusion (e.g., versus removing a contact from a single audience), and no reference to alternatives. Usage is inferable but not guided.

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