Update a subscriber's pinned location

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

Annotations already carry destructiveHint=true, idempotentHint=false, and openWorldHint=true, so the safety profile is largely covered. The description still adds real value by naming the blast radius ('may affect delivery, audience membership, published data or irreversible state') and the confirm gate, going beyond what the structured fields say.

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 tight sentences, zero filler, with the impactful mutation-risk and confirm-requirement information placed immediately after the purpose statement.

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, 6-parameter mutation tool with no output schema, the description covers purpose, risk, and the confirm gate, which is most of what an agent needs. It stops short of explaining how the nested location parameters or payload/payload_file alternatives interact, though the schema handles that.

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 83%, so the schema already documents confirm, payload, payload_file, and subscriber_id. The description reinforces the confirm requirement but adds no syntax, format, or exclusivity detail beyond the schema (e.g. payload vs body flags).

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 ('Update a subscriber's pinned location'), which is clearly distinct from siblings like get_subscriber or update_subscriber. However, it does not differentiate itself from the close sibling pin_subscriber_location, leaving the agent to infer the boundary between the two.

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?

The description supplies a trigger condition ('Requires confirm=true') but never states when to choose this over pin_subscriber_location or delete_subscriber_location. Usage is implied rather than explicit, and no prerequisites beyond confirm are given.

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