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

With no annotations, the description carries the full burden. It does useful work by enumerating the return fields (line numbers, line text, spellings, permalink) and implying variant spellings are matched, but it says nothing about no-match behavior, ordering, or access constraints for a tool with zero annotation coverage.

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 sentence, front-loaded with the input then the output contract via a colon list. Every clause adds information; no filler.

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, one-parameter lookup with no output schema, the description supplies the missing return shape and the external link source. Only the no-results case and matching rules remain undocumented, which is a minor but real gap.

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% and the single parameter already documents 'Old English headword to locate in Bēowulf' with an example. The description's phrase 'Old English headword' merely restates that, adding no format or scoping detail beyond the schema.

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 names a specific verb and resource: return every line of Bēowulf carrying a given Old English headword. That is unambiguous and clearly distinct in subject matter from the morphological siblings (inflect, identify_form), though it never names an alternative to route against.

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?

Saying 'Given an Old English headword' implies a prerequisite (the input must be a headword, not an inflected form) but stops short of telling the agent to use identify_form or lookup_headword first. No when-not conditions or explicit alternatives are given.

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