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

The description discloses several important behaviors beyond the annotations: it requires an API key and incurs cost per character (a side effect not implied by readOnlyHint=false), it falls back to text if no voice exists for the language, it always speaks Scripture in English (KJV) and never translates it, and it outlines a two-step flow. These are critical for an agent to call the tool correctly and to manage member expectations. The annotations only provide idempotentHint and destructiveHint, so the description carries the full burden, and it does so thoroughly.

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 description is relatively long (about 150 words) but every sentence carries necessary information for a tool with seven parameters and a complex two-step workflow. It is structured logically: purpose first, then language handling, then scripture rule, then the two-step process. While it could be tightened slightly, the length is justified by the tool's complexity, so it is concise relative to the required nuance.

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?

Given the tool's complexity (7 parameters, no output schema, but significant behavioral nuance), the description is very complete. It explains the return behavior ('returns audio URLs alongside the text', 'step 1 returns translate_this', 'you get both audio files back' for step 2), the cost implications, language fallback, and scripture constraints. An agent could confidently invoke this tool without needing additional clarification from the schema or external documentation.

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%, so the baseline is 3, but the description adds substantial meaning beyond the schema. It explains the relationship between consent_token and language, the fallback order, the two-step usage of reflection_text (only for non-English, step 2), and what translate_this is. It also warns about the scripture constraint for the language parameter. This contextual information is essential for correct parameter usage and is not present in 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 immediately states the tool's purpose: 'The same daily devotional, SPOKEN' – clearly indicating an audio version of the daily devotional. It specifies the resource (devotional) and the action (get audio), and implicitly distinguishes itself from the sibling get_daily_devotional by contrasting the spoken format with presumably the text version. It also mentions 'Returns audio URLs alongside the text' which further clarifies what it delivers.

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 description provides clear usage context: it is for members who prefer listening or read little, and it explains when to use the consent_token versus the language parameter. It also details the two-step process for non-English members. However, it does not explicitly name alternatives (like get_daily_devotional) or state when not to use this tool, so it falls slightly short of a 5.

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