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

Annotations already cover read-only/non-destructive/idempotent, and the description adds substantial context beyond them: the result is live and time-varying ('clears NOW', 'live transfer-pause'), the policy-resolution semantics per participant (sender policy vs. from, receiver policy vs. to, executor policy vs. operator), and service behaviors — $0.04 per-call pricing and no wallet/API key required. No contradiction with annotations.

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?

The description is front-loaded with the hook question and the core GO/HOLD/STOP mechanism before any elaboration, and each block — differentiation, policy detail, cost, auth — earns its place. Minor waste: 'Required inputs: address, from, to' duplicates the schema's required array, and the x-credit-token header/free-tier clause is more verbose than necessary.

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?

Given rich annotations and an output schema, the description covers the essentials: purpose, per-parameter roles, liveness, differentiation from siblings, cost, and auth requirements. The remaining gap is action semantics — what an agent should do upon receiving GO vs. HOLD vs. STOP is left implicit rather than stated.

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 100%, so the baseline is 3. The description adds meaning by mapping each parameter to its role in the check: sender policy resolved against 'from', receiver policy against 'to', executor policy against the operator, and 'address' identified as the token. It reinforces the schema's 'transferFrom operator' hint with the reason the executor matters. It does not add new format or constraint details beyond the 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?

Opens with the question 'Will THIS transfer (from→to) clear right now?' and immediately specifies the deliverable: 'get one GO/HOLD/STOP on whether this exact transfer clears NOW'. It explicitly separates itself from siblings — 'Every other B20 tool is per-token due diligence bought once; this is the check an agent runs on every payment' — and from ERC-20 tools ('No ERC-20 tool can see it').

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?

'This is the check an agent runs on every payment' states the when-to-use condition directly, and 'Every other B20 tool is per-token due diligence bought once' implies when not to use it (one-time due diligence). The pricing and free-tier detail also support cost-aware routing. However, it does not name specific alternative tools (e.g., b20_access_type, b20_gate, pre_trade_gate), leaving the when-not condition at the group level.

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