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lom_call

Invoke an allowlisted method on a Live object via its dotted path and method name. Use only when no dedicated tool exists; prefer create_clip, delete_track, set_tempo, and similar tools.

Instructions

Invoke an allowlisted method on a Live object.

The escape hatch for the calls that have no tool of their own, such as
``song.move_device`` for reordering a device chain. What it can reach is bounded
by the Remote Script's allowlist, not by this signature.

Returns:
    Dictionary reporting the call and its return value. A refused call names the
    reason, and where a dedicated tool covers the same ground it comes back with
    ``use_instead`` naming that tool.

Note:
    A method call has no read-back, so nothing here proves the effect the way a
    write through lom_set or set_parameter does. Follow it with the matching read
    (get_devices after a move, get_session after a structural change) rather than
    treating a successful return as evidence.

    Prefer the dedicated tool wherever one exists: create_clip, delete_track,
    set_tempo, play and stop all verify what this cannot. Use lom_get and lom_set
    for properties, which are not reachable as methods, and lom_batch to send
    several calls in one round trip.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
argsNoPositional arguments, in order. Keyword arguments are not supported. A Live object is passed as a reference dict, {'__path__': 'song.tracks[2]'}, rather than as a name or an index.
pathYesDotted LOM path to the object the method sits on, e.g. 'song' for song.move_device or 'song.tracks[0]' for a track method. The object that owns the method, not the object being acted on.
methodYesMethod name to invoke, e.g. 'move_device'. Only names on the Remote Script's allowlist are accepted; lom_describe lists the ones permitted on a given object.

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. Changed3 schema fields changedv0.1.1
    • addedInput schema / properties / args / description
      Added value: +"Positional arguments, in order. Keyword arguments are not supported. A Live object is passed as a reference dict, {'__path__': 'song.tracks[2]'}, rather than as a name or an index."
    • addedInput schema / properties / method / description
      Added value: +"Method name to invoke, e.g. 'move_device'. Only names on the Remote Script's allowlist are accepted; lom_describe lists the ones permitted on a given object."
    • addedInput schema / properties / path / description
      Added value: +"Dotted LOM path to the object the method sits on, e.g. 'song' for song.move_device or 'song.tracks[0]' for a track method. The object that owns the method, not the object being acted on."
  2. First observedv0.1.0

TDQS

A4.7/5.0
Behavior5/5

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

The description discloses a critical limitation: 'a method call has no read-back, so nothing here proves the effect' and recommends following with matching reads. It also explains the return behavior, including refused calls naming the reason and 'use_instead' pointing to a dedicated tool. The annotations are all false and are not contradicted; the description adds substantial behavioral context beyond those booleans.

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 is front-loaded with the core purpose and then uses labeled sections for return behavior and usage notes. Every sentence adds information: the allow list boundary, the no-read-back caveat, the follow-up-read recommendation, and the explicit alternatives. It is longer than a one-liner but earns its length for such a generic escape-hatch tool.

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

Completeness5/5

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

For a generic fallback tool with three parameters and an output schema, the description covers what an agent needs: what it calls, how it is restricted, what the return dictionary contains, how to verify effects, and when to choose a sibling tool. The presence of an output schema means the return-value structure need not be fully repeated here. No critical operational context appears missing.

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

Parameters3/5

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

The input schema already provides 100% coverage with detailed descriptions for path, method, and args, including the reference-dict format for Live objects. The description itself adds contextual examples like 'song.move_device' but does not attempt to redefine the parameters. A baseline score of 3 is appropriate because the schema carries the parameter-semantics load.

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 immediately states the verb and resource: 'Invoke an allowlisted method on a Live object.' It then clarifies that this is the 'escape hatch' for calls with no dedicated tool, using 'song.move_device' as a concrete example. This clearly distinguishes it from the many sibling tools that cover specific operations.

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?

The description explicitly says to prefer a dedicated tool wherever one exists, names several such tools, and directs property access to lom_get/lom_set and multiple calls to lom_batch. It also instructs the agent to follow up with a matching read because method calls have no read-back. This is explicit, actionable routing guidance.

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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