Simpler.Asia

studio.move_caption

Move ONE whole caption row along the timeline by delta_ms (negative moves it earlier): its start, its end and every word timing move together, so the words keep their spacing. Pick the row by caption_id, or by at_ms: the visible caption showing at that timeline millisecond (hidden rows are skipped). The row stops at 0, at the timeline cap and at the visible caption on either side, so a move never runs into its neighbours. To change only a start or an end, use edit_caption. Refuses, naming the fix: neither caption_id nor at_ms given, an unknown caption_id, no visible caption at at_ms, or a delta_ms outside the range that fits (the refusal gives that range).

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "project_id": "<project_id>",
      "delta_ms": "<delta_ms>"
    },
    "name": "studio.move_caption"
  }
}

Input Schema

Name	Required	Description
`at_ms`	No	A timeline millisecond inside the visible caption to move; used when caption_id is left out.
`delta_ms`	Yes	Milliseconds to move the whole row; negative moves it earlier.
`caption_id`	No	The caption row (vc_) to move. Leave it out and pass at_ms instead to pick the row showing then.
`project_id`	Yes	The studio project (vp_…) this tool acts on.

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 23, 2026

TDQS

A4.3/5.0

Behavior3/5

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

Annotations only declare readOnlyHint=false, and the description goes well beyond that: it discloses clamping at 0, at the timeline cap and at neighbouring visible captions, and enumerates the exact refusal cases (missing selector, unknown caption_id, no visible caption at at_ms, out-of-range delta) including that the refusal names the fix. That is strong mutational context. It stops short of saying whether the move is atomic/undoable or what the response contains, so it is a solid but not complete behavioural account rather than a perfect 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The core action and the delta sign are front-loaded, and the edit_caption fork and refusal list follow logically; nearly every clause carries information. It is a dense single paragraph, though, with the selector rule and the clamping rule interleaved, so scanning it takes more work than a bulleted or shorter phrasing would.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 4-parameter mutation with no output schema, the description covers selection, effect scope, clamping and every failure mode, which is what an agent needs to call it correctly. The remaining gap is the return value (e.g., the row's new start/end), which is unstated and not recoverable from an output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds meaning the schema does not: that at_ms selects the *visible* caption at that millisecond with hidden rows skipped, that caption_id and at_ms are alternatives, and that negative delta moves earlier. The delta sign is largely restated from the schema, keeping this just under a 5.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Move ONE whole caption row along the timeline by delta_ms') and immediately scopes the effect to start, end and every word timing. It explicitly distinguishes itself from edit_caption, which is the nearest sibling for partial edits, so an agent can pick correctly without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives explicit routing rules: use this tool for whole-row moves, use edit_caption to change only a start or an end. It also states the two mutually exclusive ways to select the row (caption_id, or at_ms for the visible caption at that millisecond with hidden rows skipped), so there is nothing left to infer.

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

All Simpler.Asia tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?