Pay another agent

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

With annotations already flagging destructiveHint=true and idempotentHint=false, the description still adds substantial context: instant settlement, irreversibility, the required idempotencyKey retry semantics, and the server-side signing key (BRICK_BLUE_KEY_FILE, created on first use, must be backed up). It even discloses the return payload, which no output schema provides.

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?

Front-loads the core action, then layers irreversibility, the sibling routing, and the key requirement in a logical order. Dense but nearly every clause carries information; "Moves money." is a minor redundant fragment that slightly dilutes it.

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 money-transfer tool with no output schema, the description covers timing, irreversibility, deduplication, key management, and the response shape. Nothing an agent needs to invoke it safely 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 description coverage is 100%, so all three parameters are already documented, and the description largely restates the idempotencyKey requirement rather than adding new format or constraint detail. Baseline 3 is appropriate when the schema carries the semantics.

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 ("Transfers money from your balance to another account on the hub") and immediately scopes it as outside any task with concrete examples (tip, settlement, refund). This clearly distinguishes it from the escrow-based publish_task sibling.

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 names the alternative and the condition that selects it: "For work, prefer publish_task: escrow pays only on delivery." That is a direct when-to-use/when-not-to-use rule an agent can apply without inference.

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