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

Annotations already declare destructiveHint=true and openWorldHint=true, so the bar is lower, yet the description adds real substance: unsubscribing also suppresses the address, suppressed addresses cannot be resubscribed here, and subscribing can trigger journeys starting on 'Subscribed'. The notable omission is the confirm/dry-run behavior, which lives only in the schema, not the description.

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?

Three dense sentences, front-loaded with the core action and free of filler; each sentence carries a constraint or side effect. The first sentence is slightly tangled with its nested 'subscribed only when...' clause, which costs a point.

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 destructive, non-idempotent mutation with no output schema, the description covers the side effects, the suppression interaction, and the resubscribe prohibition. What is missing is the two-step confirm default (changes nothing unless confirm=true), which an agent must read from the schema to avoid unintended writes.

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?

With 75% schema coverage the baseline is 3, but the description adds meaning the schema does not: it explains what each consent enum value represents in human terms and ties 'source' to 'where and how' consent was given. It does not address contactId or confirm, which the schema already documents.

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?

States a specific verb and resource ('Records a contact's marketing consent') and enumerates the two states it sets. It implicitly separates itself from the workspace-level get_consent_settings/update_consent_settings siblings, but never names an alternative tool explicitly, so differentiation is left to inference.

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?

Gives clear conditions for each branch: use subscribed 'only when the person says the contact really agreed', unsubscribed 'when they asked to stop'. It also supplies a when-not rule ('An unsubscribed or suppressed address cannot be subscribed this way'). No alternative tool or escalation path is named, so it stops short of 5.

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