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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safe read profile is covered. The description adds cost behavior, but then contradicts itself: 'Free (0 credits)' followed by '[Cost: see your plan — endpoint not in the public credit manifest]', which leaves the agent unable to know whether this costs credits.

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?

Front-loads the purpose in one sentence, then the query defaults and cost. The group/cost metadata lines are boilerplate but short; nothing egregious.

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?

With an output schema present and full parameter coverage, return values need not be explained. However, the self-contradictory cost line and the absent guidance on how this glossary relates to the translate_* siblings leave gaps for a localization-family tool.

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 lang, fields and precision are already well documented and baseline 3 applies. The description instead describes query parameters that do not exist in the schema (?source, ?domain), which adds marginal, mildly confusing context rather than clarifying the actual inputs.

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 and resource: 'Download the astrology glossary for a target language' — an agent can tell this retrieves glossary content rather than translating astro text (translate_astro) or listing locales (translate_languages). It does not explicitly name the closest siblings, but the noun 'glossary' separates it adequately.

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?

No statement of when to use this versus the sibling translation/localization tools. It supplies default values for query options (source=en, domain=generic) and a cost note, but nothing about prerequisites or selection conditions.

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