registry.abi_selectorReturns an exact selector for a reviewed read ABI function using an interface and signature, so you can identify read calls without deploy or transaction authorization.
Return an exact selector for a reviewed read ABI function, not a deploy/transaction authorization.
| Name | Required | Description | Default |
|---|---|---|---|
| interface | Yes | ||
| signature | Yes |
Changes observed during successful MCP inspections.
v0.9.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so safety is covered. The description adds the meaningful constraint that only 'reviewed' ABIs are served and that the output is a selector rather than an authorization, but it says nothing about failure behavior for unreviewed or unknown signatures.
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 front-loaded sentence with no filler. Its brevity is a virtue in structure but contributes to the under-specification noted elsewhere.
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 tool with two required, entirely undocumented parameters and no output schema, the description does not say what a 'selector' looks like on return (hex length/format) or how the two inputs combine. An agent can guess but cannot be certain it is calling this correctly.
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 0% and both parameters are required, so the description carries the full burden — yet it explains neither what 'interface' identifies (network, contract, interface name?) nor that 'signature' is presumably a canonical function signature string. Only a loose hint is derivable from the phrase 'ABI function'.
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 verb+resource ('Return an exact selector for a ... ABI function') is present and the negative clause rules out deploy/transaction authorization. However, 'selector' and 'ABI function' are left undefined, and the sibling registry.abi_catalog is never referenced, so the boundary between this tool and that catalog is not established.
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 a 'what this is not' (not a deploy/transaction authorization) but no positive when-to-use condition and no named alternative such as registry.abi_catalog or registry.verify_contract. The agent must infer the selection rule from a negation alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.