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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering safety. The description adds value by explaining the return behavior for verified vs unverified contracts (match_type 'full'/'partial'/'none') and the default chain behavior, which goes beyond the 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 three concise sentences, front-loaded with the core purpose. Every sentence provides useful information: what it fetches, what it returns, and default behavior. No filler or 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?

Despite no output schema, the description explains the return value (ABI array and match type) and handles the edge case of unverified contracts. It also notes the default chain_id, making the tool self-contained for a simple read operation.

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 description coverage is 100%, so the schema already documents both parameters. The description reiterates the chain_id default (already in the schema) but doesn't add deeper semantics like address format requirements or how the parameters interact. Baseline 3 is appropriate.

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 clearly states the action ('Fetch a verified contract's ABI'), the resource ('from Sourcify by address'), and the return value (ABI array and match type). It also distinguishes this tool from siblings by specifying the source and purpose, which is unique among the listed tools.

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 for when to use the tool (fetching ABIs for verified contracts) and mentions the default chain_id, implying usage on Ethereum mainnet unless specified. It doesn't explicitly name alternatives or exclusions, but the sibling list shows this is the only ABI-fetching tool, so the use case is clear.

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