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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds genuinely useful behavior beyond that: the credit formula (15 + ceil(chars/40)), the 3000-char cap, and the glossary-pinning behavior. Minor caveat: it says 21 languages while the schema enum lists 20, and the cost line contradicts its own formula.

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?

The first sentence is front-loaded with the core purpose and constraints, and the bracketed metadata lines convey required params and cost compactly. No wasted prose, though the metadata block and the duplicate/internally-inconsistent cost figures add slight noise.

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?

An output schema exists, so return values need no explanation, and the description supplies cost, length limits, and the source-language default. The main gap is the completely unexplained 'domain' parameter, which is central to the astro-glossary feature.

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 only 33%, so the description must compensate and only partly does: it clarifies source_lang defaulting to English and the text length cap. The 'domain' enum (vedic/western/tarot/etc.) is undocumented in both schema and description, leaving the glossary-selection parameter opaque.

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 states a specific verb+resource ('Translate one text') with the distinguishing traits of the astro variant: astrology-domain glossary pinning and single-text scope. That implicitly separates it from the sibling translate_batch and translate_glossary_lang tools, though neither sibling is named explicitly.

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?

It gives the source-language default and how to override it ('pass source_lang'), which is a useful usage hint. However, it never says when to choose this over translate_batch or translate_glossary_lang, so the agent is left to infer routing from the name.

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