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

Annotations already declare destructiveHint=true and idempotentHint=false, but the description adds real context beyond them: the other person is never notified, and the relationship resets to nothing rather than to a contact pair. It does not cover behavior when the contact is not currently blocked, which matters given the non-idempotent hint.

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 short sentences, front-loaded with the action and its effect, followed by the consequence and the usage restriction. Every sentence carries distinct information with no repetition of the schema or annotations.

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 one-parameter, no-output-schema tool with annotations covering the safety profile, this is nearly complete: it explains the semantic outcome and the notification posture. The only missing piece is edge-case behavior when no block exists, which the non-idempotent annotation makes relevant.

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 single parameter is fully documented in the schema, including that it accepts an email or a name as shown among the blocked in list_contacts. The description adds no syntax or format guidance beyond that, so the baseline 3 for high schema coverage 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?

States a specific verb and resource ("Lift a block the user set") and immediately clarifies the resulting state: two accounts with no relationship, not a contact pair. It also names the sibling that restores correspondence (invite_contact), so an agent can distinguish this from block_contact, accept_contact, and invite_contact without opening a 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?

Gives an explicit gating condition ("Call it only when the user asks for it in their own message"), which prevents an agent from proactively chaining it. It also spells out the alternative path: re-establishing correspondence requires invite_contact, so the agent knows this tool cannot substitute for it.

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