Play Audiobook via Audible

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'Play an audiobook from Audible on an Echo device' and does not disclose what happens if the audiobook is not found, whether playback starts immediately, whether it interrupts current audio, or whether it requires an Audible account to be linked. For a media playback tool, these are meaningful behavioral gaps.

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 a single, efficient sentence that front-loads the core action and resource. It is appropriately sized for a simple tool. It loses one point because it could have used the available space to add a brief usage hint (e.g., 'requires linked Audible account') without becoming verbose.

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 has no annotations and no output schema, the description is thin for a media playback action. An agent needs to know what happens on failure (e.g., audiobook not found), whether it requires a linked Audible account, and whether it will interrupt current playback. The sibling list shows many audio-related tools, and the description does not help an agent distinguish when to use this one versus alexa_play_music or alexa_play_sound.

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 both parameters. The description adds no additional parameter-level meaning beyond what the schema provides. The serialNumber description in the schema usefully references alexa_list_devices, but the tool description itself does not add value here. Baseline 3 is appropriate.

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 ('Play'), a specific resource ('an audiobook from Audible'), and a target device ('an Echo device'). It clearly distinguishes from siblings like alexa_play_music and alexa_play_sound by naming the Audible source. However, it doesn't explicitly contrast with those siblings, so it doesn't earn a 5.

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 implies the tool is for playing Audible audiobooks on Echo devices, which is clear enough for basic selection. It does not state when to prefer this over alexa_play_music or alexa_play_sound, nor does it mention prerequisites like the audiobook being in the user's Audible library. The schema's serialNumber description does point to alexa_list_devices, which is a useful routing hint, but the main description lacks explicit usage guidance.

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