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

Annotations mark the tool as non-read-only and non-idempotent, and the description expands on this by disclosing that synthesis consumes organization credits, is billable, and that repeating the call creates another segment and synthesizes again. This is exactly the kind of behavioral context an agent needs before invoking a state-changing tool.

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?

Three information-dense sentences with no filler. Purpose, billing implications, the url alternative, and non-idempotency are all communicated efficiently and 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 state-changing, billable tool, the description covers all critical operational facts: new segment creation, credit consumption, the url escape hatch, and repeat-call behavior. Parameters are fully documented in the schema and an output schema exists, so the agent has everything needed to call it correctly.

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 all six parameters are already documented. The description adds context about text-versus-url behavior but does not need to explain projectId, language, voice, or translatedText, so the baseline score of 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?

States a specific verb and resource: 'Create one Tutorializer voiceover segment for a project.' It also distinguishes two modes—synthesizing from text versus registering a url—so the agent understands exactly what the tool does and how it differs from other create_* tools.

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?

Clearly explains when to use the synthesis path versus passing a url to register already-produced audio. It does not explicitly name sibling tools like update_speech as alternatives, but the within-tool usage decision is fully specified.

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