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

With no annotations, the description carries the full burden and does reasonably well: it discloses the coverage boundary (only 8 major tokens and 'common spenders', with named examples), states a distinguishing output behavior (unlimited-approval flagging), and volunteers the price ($0.005). It does not state that it is read-only or describe response shape, so it stops short of full disclosure.

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 tight sentence front-loads the operation and scope, with the coverage caveat and price appended in a compact order. No filler or repeated information from 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 one-parameter, no-annotation, no-output-schema tool, the description supplies the essentials: what is measured, which tokens/spenders are in scope, what the headline output is, and the cost. Remaining gaps (result structure, whether non-listed spenders are ignored entirely) are minor but not negligible.

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 single 'address' parameter has 0% schema description coverage (only a hex pattern), so the description must compensate — and it does by making clear the address is a Polygon wallet address whose ERC-20 allowances are read. Format/chain expectations are implied rather than spelled out, keeping it below a 5.

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 ('Check a Polygon wallet's ERC-20 approvals') and enumerates the token/spender scope plus the key output behavior ('flags unlimited approvals'). This distinguishes it from chain-siblings like polygon_address_inspect, polygon_contract_risk and polygon_tx_explain by the resource examined, though it never names an 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?

Use case is implied by 'Check ... approvals' (an allowance-exposure/security check on a Polygon wallet), but there is no explicit when-to-use, no when-not-to-use, and no routing to or away from the other Polygon tools. The agent must infer that this is the approval-audit call rather than the risk or address-inspect call.

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