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

With no annotations, the description does real work: it discloses that the tool is free and offline (no network calls), explains the lookalike algorithm ('same first/last hex chars, different middle'), and mentions checksum validation. It does not describe the return shape (boolean vs. detailed result), which is a gap absent an output schema.

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?

A single dense sentence with the core check front-loaded and the call-to-action at the end. No filler; every clause adds meaning.

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 two-parameter read-only check, the description covers purpose, safety profile (offline/free), and trigger condition well. The main missing piece is what the tool returns, which matters because there is no output schema.

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%, and the schema descriptions already explain 'to' as the recipient about to be paid and 'known' as trusted addresses. The description adds no parameter-specific detail beyond reinforcing the trusted-address concept already in 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?

States a specific check (lookalike comparison against trusted addresses) plus EIP-55 checksum validation. The 'free, offline' qualifier also helps distinguish it from the sibling onchain_check_info, though it doesn't name that alternative explicitly.

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 a clear trigger: 'Call before every transfer to a pasted or copied address.' It doesn't state exclusions or mention when to use the sibling instead, but the usage condition is concrete and actionable.

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

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

With no annotations, the description carries the full burden, and it does disclose genuinely useful behavior: the price (0.005 USDC), the payment rail (x402 on Base), and the critical fact that it does not itself pay or transact. That is above-average for a financial tool. Missing is what the call actually returns (a 402 challenge, a quote, human-readable instructions) and whether calling it has any side effects.

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?

One dense sentence that front-loads the resource, then the purchase mechanics, then the key caveat. No filler. The compressed 'x402, 0.005 USDC on Base' fragment is terse but parseable, though slightly cryptic to an agent unfamiliar with the x402 payment scheme.

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?

There is no output schema, no annotations, and no parameters, so the description is the sole source of truth. It covers cost, chain and scope but omits what the response payload looks like and how the agent should act on it, which matters for a purchase-flow tool whose entire value is the returned instructions.

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 tool takes zero parameters and the schema is an empty object, so there is nothing for the description to disambiguate. Baseline 4 applies; no parameter-level guidance is needed or missing.

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?

The description states a clear resource: it returns purchase information for the hosted on-chain check that scans a sender's transfer history on Ethereum, Base and Avalanche for poisoning transfers and lookalikes. It also disambiguates the action from the underlying scan by saying 'Does not pay', so an agent knows this is informational rather than transactional. It does not, however, name or differentiate itself from the sibling check_recipient_lookalike.

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 clause 'Does not pay' implicitly tells the agent this endpoint provides instructions rather than executing a purchase, which is useful routing context. But there is no explicit statement of when to call this versus check_recipient_lookalike, and no indication of prerequisites or next steps after receiving the purchase instructions.

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