Replace Clip

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

With annotations only declaring mutation/safety flags, the description carries the behavioral burden well: it explains the replacement plays from its own In mark for the original duration, that neighbouring clips do not ripple, that a linked partner on another track is left in place, and that a locked track causes a no-op refusal. It also discloses the three readback outcomes (verified, committed_unverified, failure with Undo guidance), which is exactly the kind of post-condition detail annotations cannot convey.

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 core action is front-loaded in sentence one, and the following sentences each add distinct information (ripple/link behaviour, locked-track refusal, verification states). The third sentence is dense with implementation vocabulary, but nothing is redundant.

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?

The tool has an output schema plus annotations, and the description still covers the mutation semantics, side-effect boundaries, failure mode, and verification outcomes an agent needs to call and interpret it correctly. Nothing material is left unstated.

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% for both parameters, so node_id and new_item_id are already documented in the schema. The description adds useful semantics about what the new item's In point means during playback, but it does not clarify formats or how 'name' lookup works for new_item_id. Baseline 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?

The description gives a precise verb+resource ('Replace one timeline clip with a different project item on the same track') and immediately scopes it with the constraint that exact timeline start and end are preserved. It is clearly distinguished from generic overwrite/split tools, but it never mentions the sibling 'replace_clip_media', which is the most likely confusion candidate.

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?

Usage is implied through stated preconditions — it refuses when the track is locked, and it preserves neighbours and linked partner clips — so the agent can infer when it is appropriate. However, there is no explicit 'use this instead of X' guidance, and the distinction from replace_clip_media is left to inference.

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