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

Annotations already flag destructive and idempotent behavior, but the description goes further by explaining the mechanism (re-synthesis with the project's speech provider), the cost (synthesis credits), the consequence (previous audio is replaced), and the no-op case. This adds real behavioral context beyond the annotation flags and does not contradict them.

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?

Two dense sentences: the first states the operation and scope, the second explains side effects and no-op behavior. There is no filler, no repetition of schema content, and the most decision-relevant information is front-loaded.

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 5-parameter tool with an output schema and informative annotations, the description covers all the non-schema knowledge an agent needs: re-synthesis behavior, credit consumption, audio replacement, and the no-op condition. Nothing material is missing for correct invocation.

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?

The input schema already documents all 5 parameters with descriptions, so schema coverage is 100%. The description adds only a general rule that each listed field determines the audio, which is useful context but does not need to repeat per-parameter details already 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?

States a specific action ('Change') and a precise resource ('one Tutorializer voiceover segment'), and enumerates the affected fields: text, translation, language, and voice. This clearly distinguishes it from the sibling update_project/update_tutorial/update_video tools by naming the voiceover segment and its re-synthesis behavior.

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 makes clear this is for editing an existing voiceover segment rather than creating one, and gives a practical condition: only real field changes trigger re-synthesis while unchanged values are a no-op. It does not explicitly name alternatives like create_speech, but the context is unambiguous enough for an agent to select the tool correctly.

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