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

Annotations already declare idempotent=true, destructive=false, readOnly=false, so the safety profile is covered; the description adds beyond that by spelling out the idempotency behavior in human terms ("Adding a demo that is already in it changes nothing"), the viewer-visibility consequence of demo state, and required scopes demos:read/demos:write. It still omits return value and error behavior (e.g., out-of-range position), so not a 5.

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 short paragraphs, front-loaded with the core action and ordering semantics, then the permission requirement. Every clause carries information an agent would otherwise have to guess.

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 mutation with rich annotations but no output schema, the description covers ordering, overrides, idempotency, visibility, and auth scopes. The only gaps are error/edge behavior (invalid position, non-existent collection) and whether anything is returned, which are minor for this tool's complexity.

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 40%, with title, position, and description undocumented in the schema; the description compensates by explaining that position is 0-based and that title/description are per-collection overrides of the demo's own values. Bounds, max lengths, and id patterns come from the schema, and the description adds no syntax guidance beyond that, so 4 rather than 5.

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 ("Adds a demo to a collection's list") plus the exact insertion semantics (end of list or 0-based position). No sibling does this, and the sentence reads unambiguously as a collection-membership mutation rather than a demo/scene/step edit.

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 you must already know a collectionId and demoId (with list_collections/list_demos implied as the source) and warns that only live demos are visible to viewers, which shapes when this is worth doing. It stops short of naming an alternative tool or stating when not to use it, so it is strong context without explicit exclusions.

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