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insert_envelope_point_at_beat

Add automation envelope points aligned to the beat grid in REAPER projects. Specify envelope by name or index, position by bar and beat, and set value and shape for precise audio parameter control.

Instructions

Insert an automation envelope point aligned to the project beat grid. Identify the envelope by name (e.g. 'Volume', 'Pan') or by 0-based envelope_index.

  • bar: 1-based measure number (bar 1 = project start)

  • beat: 1-based beat within the bar, may be fractional (e.g. 2.5 = beat 2 and a half). Beat units follow the time-signature denominator (e.g. quarter notes in 4/4, eighth notes in 6/8).

  • value: linear amplitude (Volume: 0.0=silence, 1.0=0 dB, 2.0=+6 dB max)

  • shape: 0=linear, 1=square, 2=slow start/end, 3=fast start, 4=fast end, 5=bezier Returns the resolved time in seconds alongside bar/beat for verification.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
track_indexYes
barYes
beatYes
valueYes
envelope_indexNo
envelope_nameNo
shapeNo
tensionNo

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Implementation Reference

  • The handler function for 'insert_envelope_point_at_beat' which validates the inputs and calls the adapter.
    def insert_envelope_point_at_beat(
        track_index: int,
        bar: int,
        beat: float,
        value: float,
        envelope_index: int | None = None,
        envelope_name: str | None = None,
        shape: int = 0,
        tension: float = 0.0,
    ) -> dict[str, Any]:
        """
        Insert an automation envelope point aligned to the project beat grid.
        Identify the envelope by name (e.g. 'Volume', 'Pan') or by 0-based envelope_index.
        - bar: 1-based measure number (bar 1 = project start)
        - beat: 1-based beat within the bar, may be fractional (e.g. 2.5 = beat 2 and a half).
          Beat units follow the time-signature denominator (e.g. quarter notes in 4/4, eighth notes in 6/8).
        - value: linear amplitude (Volume: 0.0=silence, 1.0=0 dB, 2.0=+6 dB max)
        - shape: 0=linear, 1=square, 2=slow start/end, 3=fast start, 4=fast end, 5=bezier
        Returns the resolved time in seconds alongside bar/beat for verification.
        """
        try:
            return _wrap(
                adapter.insert_envelope_point_at_beat(
                    track_index=track_index,
                    envelope_index=envelope_index,
                    envelope_name=envelope_name,
                    bar=bar,
                    beat=beat,
  • MCP tool registration decorator for 'insert_envelope_point_at_beat'.
    @mcp.tool()
    def insert_envelope_point_at_beat(
  • Adapter method that forwards the request to the REAPER bridge client.
    def insert_envelope_point_at_beat(
        self,
        track_index: int,
        bar: int,
        beat: float,
        value: float,
        envelope_index: int | None = None,
        envelope_name: str | None = None,
        shape: int = 0,
        tension: float = 0.0,
    ) -> dict[str, Any]:
        return self._client.call(
            "insert_envelope_point_at_beat",
            track_index=track_index,
            envelope_index=envelope_index,
            envelope_name=envelope_name,
            bar=bar,
            beat=beat,
            value=value,
            shape=shape,
            tension=tension,
        )
Behavior4/5

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

With no annotations provided, the description carries significant behavioral weight: it documents the return value format ('resolved time in seconds'), value scaling for Volume (0.0 to 2.0 mapping), shape interpolation codes (0-5), and beat unit semantics relative to time signatures. Minor gaps include lack of explanation for the 'tension' parameter and whether inserting a point overwrites adjacent points.

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

Conciseness5/5

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

The description employs an efficient structure: a single declarative sentence stating purpose, followed by envelope identification guidance, then bullet points for complex parameters. Every line conveys essential timing or value semantics without redundancy.

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 an 8-parameter DAW automation tool with specific domain concepts (time signatures, envelope shapes), the description adequately covers the complex interacting parameters. Despite the presence of an output schema, it helpfully previews the return value format, though completion would require documentation of the 'tension' parameter and track indexing convention.

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?

Given 0% schema description coverage, the description compensates exceptionally well by documenting critical semantics: bar/beat are 1-based (with specific examples), value uses linear amplitude with concrete dB mappings, and shape enumerations are decoded. Only 'track_index' (0-based vs 1-based?) and 'tension' are left undocumented in the description text.

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?

The description opens with a specific action ('Insert') and resource ('automation envelope point'), and immediately distinguishes this tool from sibling 'insert_envelope_point' by emphasizing the 'project beat grid' alignment. This specificity allows an AI agent to confidently select between the two insertion methods.

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

Usage Guidelines3/5

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

While the description implicitly distinguishes this tool via the beat-grid alignment and bar/beat parameters, it does not explicitly state when to use this versus 'insert_envelope_point' (which presumably uses time in seconds), nor does it clarify whether 'envelope_name' or 'envelope_index' takes precedence when both are provided.

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

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