check_allowance

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

No annotations are provided, so the description must carry the transparency burden. It explains the semantic meaning ('how many tokens an owner has approved a spender to use') which is genuinely informative. However, it doesn't describe return value format, whether it reverts for invalid tokens, or any edge-case behavior. With zero annotations, this is adequate but not rich.

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 sentences, zero wasted words. The first sentence states the purpose, the second provides usage context. Everything earns its place with no redundancy.

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 simple read-only query with 3 fully-described parameters and no output schema, the description is largely sufficient. It would benefit from noting the return format (allowance value) since there's no output schema, but the purpose is clear enough that an agent could reasonably use it. The use-case guidance adds valuable context not in the 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% — all three parameters have descriptions in the schema (token, owner, spender addresses). The description reinforces the roles ('owner has approved a spender') but doesn't add format details or validation constraints beyond the schema. Baseline 3 is appropriate since the schema already does the heavy lifting.

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?

Specific verb+resource: 'Check ERC-20 token allowance' clearly states what it does. It names all three involved parties (owner, spender, token) and explains the approval concept. Distinguishes from siblings like check_balances and get_token_info by its specific purpose.

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 description provides clear context: 'Useful before executing swaps or transfers that require approval.' This gives a concrete scenario where the tool is relevant. While it doesn't explicitly name alternatives or state when NOT to use it, the use-case framing is strong and positions it relative to swap/transfer workflows.

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