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

Annotations provide no behavioral hints (all false), so the description carries full responsibility. It discloses project scoping ('PROJECT-SCOPED: this call acts only on the explicit project_id'), return behavior ('returns the project identity with its result'), audio behavior ('plays once, for as long as the sound is, and never ducks'), and timing semantics. This is comprehensive given the absence of annotation support.

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 lengthy but every sentence adds value: scoping, usage, exclusions, parameter guidance, and default. It is front-loaded with project scoping and maintains a logical flow. While dense, it avoids redundancy and each sentence earns its place, making it appropriately structured for the tool's complexity.

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?

With no output schema, the description explains the return value ('returns the project identity with its result'). It covers all parameters, usage context, prerequisites, and exclusions. It also addresses potential uncertainty ('uncertainty is something to judge rather than a reason the tool becomes unavailable'). This is a complete and self-sufficient description for a complex tool.

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 only 17% (only project_id has a description). The description compensates by explaining storage_key (exact key from fetch_sfx or list_assets), at (output-timeline second), offset_s (starts inside source audio), purpose (records event for review), and the default -6dB gain. This covers all parameters meaningfully, far exceeding schema detail.

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 clearly states the tool's purpose: 'Punctuate a MOMENT with a one-shot sound effect' and gives concrete examples (whoosh, click, impact). It explicitly differentiates from background music, aligning with sibling tools like add_music and add_voiceover. The verb 'add' combined with the resource 'sfx' is specific and unambiguous.

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?

Provides explicit usage conditions: 'Choose it when the brief, format, timing, or your editorial judgment says sound design improves the cut.' It also states a clear exclusion: 'This is NOT background music: it plays once, for as long as the sound is, and never ducks.' Additionally, it specifies the source for storage_key, guiding the agent on valid inputs and prerequisites.

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