google-flow-mcp

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Update character

flow_update_character

Update a Google Flow character's name, voice, or personality notes to keep AI video characters consistent across projects.

Instructions

Change a character's name, voice or personality notes.

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>",
      "character_id": "<character_id>"
    },
    "name": "flow_update_character"
  }
}

Input Schema

Name	Required	Description
`name`	No
`voice`	No
`project_id`	Yes	Flow project id (from flow_list_projects).
`personality`	No
`character_id`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 27, 2026

TDQS

C2.9/5.0

Behavior2/5

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

With no annotations, the description carries the full burden. It says the tool 'changes' fields but omits whether omitted fields are preserved, what permissions are required, whether changes are reversible, or what the response contains.

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?

A single, front-loaded sentence with no filler. Efficient, though it is arguably too terse given the unaddressed behavioral and parameter gaps.

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

Completeness2/5

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

A mutation tool with no annotations, no output schema, and 80% of parameters undocumented in the schema. The description should disclose mutability semantics, field-omission behavior, and identifier requirements but does none of this.

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?

Schema coverage is only 20%, so most parameters are undocumented. The description names the three updatable content fields (name, voice, personality), which maps meaning onto them, but says nothing about the required project_id/character_id beyond what the one schema description already provides.

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

Purpose4/5

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

States a specific verb and resource ('Change a character's...') and enumerates the mutable fields (name, voice, personality). It is clear what the tool does, though it does not differentiate itself from the sibling flow_create_character.

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

Usage Guidelines2/5

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

No guidance on when to use this versus alternatives such as flow_create_character, nor any prerequisites (e.g. requires an existing project and character id). Usage must be inferred entirely from the name.

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