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

With no annotations, the description carries the full burden and does disclose substantive behavior: the default 5000-block window, newest-first ordering, inclusion of tx hashes, and — critically — that each call costs 0.003 USDC over x402 on Base, which an agent must know before invoking. It does not mention rate limits or what is returned when the window contains no matches.

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 dense sentences, front-loaded with the scope and ordering, followed by the usage cue and cost. Every clause carries information; only the 'incoming' phrasing is wasted because it is unsupported by the schema.

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 3-parameter paid query tool with no annotations and no output schema, the description does well on scope, cost and ordering, but omits the response shape beyond tx hashes, error/no-result behavior, and the exact semantics of the optional token filter.

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 nominally 100% but the descriptions are only bare examples ('Example: 5000'), so the description adds some real meaning by stating 5000 is a default rather than just a sample. It says nothing about what 'token' filters (a contract address) or whether omitting it returns all tokens, leaving two of three parameters semantically thin.

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 ('ERC20 transfers on Base'), plus scope (last N blocks, default 5000), ordering (newest first) and return content (tx hashes), which separates it from evm_token_balance and evm_tx. The only gap is an internal ambiguity: the schema exposes a 'token' filter while the sentence 'Use it to list incoming token transfers' implies a single direction the schema does not constrain.

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?

'Use it to list incoming token transfers' gives an implied use case but names no alternatives (evm_tx, evm_token_balance) and states no when-not conditions. An agent must infer from sibling names which tool wins for outgoing transfers or for a single token contract.

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