lookup_error

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

Annotations already mark the operation as readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds that it returns dead ends, workarounds, and error chains and notes domain coverage, but does not disclose additional behavioral traits such as rate limits or no-match behavior. Since annotations cover the safety profile, a 3 is appropriate.

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?

Three sentences, front-loaded with the core action, and every sentence carries information: purpose, return types, usage timing, domain coverage, and a pointer to a sibling tool. No wasted words.

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?

The description explains the tool's purpose, return categories, usage timing, and domain coverage, and references a sibling tool for more information. For a lookup tool with no output schema and only two parameters, this is fairly complete. Minor gaps include what happens if no match is found, but that is acceptable.

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%, with both error_message and format described. The description does not add syntax details beyond the schema; it only contextualizes that error_message comes from '51 domains,' which is minor added meaning. Baseline 3 applies.

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 'Match an error message against deadends.dev's database of known errors' with a specific verb and resource. It lists return categories (dead ends, workarounds, error chains) and distinguishes itself from siblings like list_error_domains or get_error_detail, which have different purposes.

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?

Explicitly instructs 'Use this BEFORE attempting to fix any error to avoid wasting time on approaches that are known to fail,' providing clear when-to-use context. It also points to list_error_domains for full domain lists, though it does not explicitly exclude alternatives like search_errors, so it lacks a when-not-to-use.

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