Update scene

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

Annotations already declare destructiveHint=true and idempotentHint=true, so the description doesn't need to restate those. It adds valuable behavioral context beyond the schema: a new background without width/height is measured and the scene takes its size, an empty journalIdentifier removes the link, and every change is read back. These are non-obvious side effects that an agent needs to know before calling.

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 sentences, each carrying distinct information: what can be changed, the background measurement side effect, and the journal link removal behavior. The final sentence 'Every change is read back' is a compact way to signal confirmation behavior. No filler or repetition of the schema.

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 an 11-parameter mutation tool with no output schema, the description covers the key non-obvious behaviors: background sizing, journal link removal, and read-back confirmation. It doesn't mention error conditions (e.g., what happens if the scene identifier matches multiple scenes) or whether the update is atomic, but the schema's sceneIdentifier description already covers the matching rule. The destructiveHint annotation covers the risk profile, so the description is reasonably complete.

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 73%, so the schema already documents most parameters. The description adds meaning by grouping the parameters into a coherent update operation and by explaining the interaction between name and navName ('the navigation label follows unless navName is given'). It also clarifies the journalIdentifier empty-string behavior, which the schema mentions but the description reinforces. The remaining uncovered parameters (width, height, navigation) are self-explanatory from their names and types.

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 opens with a specific verb and resource ('Change an existing scene') and enumerates the exact attributes that can be modified, which clearly distinguishes it from sibling tools like create-scene, delete-scene, or switch-scene. It also names the linked journal behavior, which is a distinctive capability not shared by the generic update-document tool.

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 implies usage context by listing the editable fields and special behaviors (background measurement, journal link removal), but it does not explicitly state when to prefer this over update-document or create-scene. The sibling list contains both update-document and create-scene, so an explicit exclusion would have been stronger, but the field-level detail gives enough context for an agent to select it for scene-specific updates.

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