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

Annotations already carry the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), and the description adds genuine context beyond them: the auto-detect behavior of source_lang and the return shape (dict with translated_text key, plus detected source language when auto-detected). No contradiction with annotations — 'translate' is consistent with readOnlyHint as a non-destructive transform. The description enriches, rather than repeats, the 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?

Well-structured: a one-line purpose statement followed by labelled Args and Returns sections, with the purpose front-loaded. The Returns section earns its place by disclosing output format absent from the schema (no output schema exists). Minor deduction for the Args block redundantly restating schema text, which adds bulk without value.

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?

Since no output schema exists, the description carries the burden of explaining return values — and it does, specifying the dict key and the conditional detected-language behavior. For a low-complexity tool (3 flat params, no nesting), this is nearly complete. Minor gaps: language code format is only implied by examples, and error behavior on invalid target_lang is unspecified, but these are marginal against an otherwise adequate definition.

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 all three parameters. The description's Args section mirrors the schema nearly verbatim (e.g., 'source_lang: Source language code; omit to auto-detect' duplicates the schema text), adding no new meaning. Per the baseline rule, with full schema coverage a 3 is appropriate — the schema does the heavy lifting and the description adds no marginal parameter insight.

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?

States a specific verb ('Translate'), resource ('text'), and scope ('between 100+ languages'). The purpose is unambiguous and clearly distinguishable from all siblings — none of the 21 sibling tools perform translation, so an agent can confidently select it.

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 Args section implies the usage pattern (provide text + target lang, omit source to auto-detect), but the description never explicitly routes the agent to or away from alternatives. Notably, sibling detect_language overlaps with the auto-detect behavior — the description doesn't tell the agent that pure language identification should use detect_language instead of translate_text. This is a missed opportunity for a tool with a directly overlapping sibling.

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