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

With no annotations at all, the description carries the full behavioral burden and largely drops it: it does not say this is a mutating write, does not mention that expectedVersion implies optimistic concurrency and a possible version-conflict failure, and says nothing about permissions or what state changes on the project. The only behavioral signal is the negative one distinguishing a scene from a timeline clip. For a create/mutation tool with zero annotation coverage this is a significant gap.

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?

A single front-loaded sentence with the core action first and the disambiguation as a trailing clause — no filler. The bracketed section references are cryptic to an agent without the spec and consume space without adding meaning, which is the only real deduction.

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 a mutation tool with 6 undocumented parameters, no annotations, and no output schema, the definition is far too thin: the agent learns the object's name and one contrast, but not the concurrency contract, the required fields' meaning, or the result. It does not give enough to call this correctly on the first attempt.

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 0% across 6 parameters, so the description must compensate and it almost entirely fails to: only "on a project" gestures weakly at projectId. Nothing explains expectedVersion semantics, plannedDurationMs units, or how narrativePurpose differs from summary. Nearly all parameter meaning must be guessed.

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 a storytelling scene") plus the parent container ("on a project"), so the agent knows exactly what object is produced. It also carves out a boundary against "a timeline clip", which is the main ambiguity risk. The opaque spec citations (§7.2, §11.3) add no machine-readable meaning, keeping it just short of 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 phrase "distinct from a timeline clip" gives one piece of when-to-use guidance and implicitly steers the agent away from timeline tools for narrative structure. However, it never names a concrete sibling (scene.update, scene.reorder, scenario.create, storyline.*) nor states prerequisites such as needing an existing project or a valid current version. Usage is implied rather than spelled out.

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