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

Annotations declare readOnlyHint=false but omit destructiveHint, so the description carries real weight: it discloses irreversibility ('It can't be undone'), the collateral effect on notes, what survives (deals remain without a contact), and the loss of opt-out records. This is exactly the kind of destruction detail an agent needs before invoking.

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 tight sentences, front-loaded with the destructive action and its scope before the safety instruction and the alternative. No filler; every clause carries load-bearing information.

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 mutation with no output schema, the description covers destruction semantics, side effects, irreversibility, a precondition, and an alternative tool. Nothing an agent needs to invoke it correctly is missing.

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 0% and the only parameter (contact_ids) is undocumented in the schema itself. The description compensates by clarifying the key type ('by id') and an operational bound ('up to 500 contacts'), adding meaning beyond the bare array-of-strings schema.

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 ('Permanently delete up to 500 contacts by id') and immediately clarifies scope ('with their notes'). It separates itself from the messaging sibling by naming crm_contact_channels, so an agent can distinguish it without opening the schema.

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?

Explicitly routes the agent to crm_contact_channels for the related-but-different intent of stopping messaging, and states the required precondition ('say who will be deleted and get a clear yes first'). Both when-to-use and the alternative case are spelled out.

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