google-flow-mcp

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Change character look

flow_regenerate_portrait

Regenerate an existing character portrait in Google Flow's character editor by applying a text instruction, such as adding a red scarf.

Instructions

Change an existing character's portrait with an instruction ("give her a red scarf"), in Flow's character editor.

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>",
      "prompt": "<prompt>"
    },
    "name": "flow_regenerate_portrait"
  }
}

Input Schema

Name	Required	Description
`prompt`	Yes
`project_id`	Yes	Flow project id (from flow_list_projects).
`character_id`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 27, 2026

TDQS

C2.8/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It implies a mutation ('change') but does not state whether the existing portrait is overwritten, whether the change is reversible, what permissions are required, 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.

Conciseness5/5

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

The description is a single, front-loaded sentence with no wasted words. It states the action, the target, the input style via an example, and the context, all efficiently.

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?

Given no annotations, no output schema, and incomplete parameter documentation, the description is too sparse for a mutation tool. It omits usage alternatives, behavioral details about overwriting or reversibility, and semantics for one of three required parameters.

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

Parameters2/5

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

Schema description coverage is only 33%. The description adds some meaning for the prompt parameter via the instruction example ('give her a red scarf'), but character_id is undocumented in both the schema and the description. project_id is described in the schema only. The description does not compensate for the low coverage.

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?

The description states a specific verb and resource: it changes an existing character's portrait using an instruction, within Flow's character editor. It is clear enough to distinguish this from general character creation or updates, but it does not explicitly name or differentiate against siblings like flow_update_character or 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?

The description gives a purpose but no explicit when-to-use guidance, prerequisites, or alternatives. It does not mention when to choose this over flow_update_character or other character-related tools, nor does it state any exclusions.

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