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

Annotations declare readOnlyHint=false and destructiveHint=false; the description adds cost information ('free'), a prerequisite for set_voice, and specific non-destructive behavior for rescan_blocks ('assets untouched; blocks whose words are unchanged keep their audio'). It does not cover error modes or what happens to blocks whose words did change.

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 compact and front-loads the action breakdown. The opening phrase 'Voices and voice blocks; free.' is slightly cryptic, but overall it uses space efficiently without unnecessary repetition.

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?

For a multi-action edit tool with no output schema and rich parameter descriptions, the description covers the three actions, prerequisites, and key behavioral effects. A small gap remains around rescan_blocks consequences when block words change, but the core call context is present.

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 six parameters and the action enum in detail. The description adds prerequisite and action context but little parameter-specific meaning beyond what the schema provides, which is the baseline-3 case.

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 enumerates three specific actions (set_voice, rescan_blocks, settings) on the voices/voice-blocks resource, making the tool's scope clear. It does not explicitly name or route against sibling tools like voiceover_read or voiceover_generate, so sibling differentiation rests on the title and schema rather than the description itself.

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 clear usage context for each action: set_voice is needed before a voiceover ('every speaker needs one before the voiceover'), rescan_blocks applies after an edit, and settings controls engine and speed. It stops short of naming alternative tools or stating when not to use the tool.

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