replace_image
Replaces an existing image's contents with a new image from a public URL, keeping the original's size and position (the new image is center-cropped to fit). image_object_id is the inline object id — read_document_text shows it inside [image:<objectId>] placeholders, and get_document lists all ids...
This record as markdown: /tools/a1-x-tech-mcp-google-docs/replace-image.md
What replace_image does on Mcp Google Docs
AI agents use replace_image to create or update resources in Mcp Google Docs, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mcp Google Docs environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
uri | string | Yes | Public URL of the new image. |
tab_id | string | — | Tab to target (from list_tabs). Omit for the first/only tab. |
document_id | string | Yes | The document id — the long id from the document URL (docs.google.com/document/d/<documentId>/edit) or from create_document output. |
image_object_id | string | Yes | The image's object id (from read_document_text [image:...] or get_document inlineObjects). |
Parameters from the server's own tool schema.
Why replace_image is rated Medium
An AI agent can call replace_image faster than any human can review: one bad instruction and it creates or modifies resources in Mcp Google Docs by the hundred, each call as confident as the last.
Risk signalsAccepts URL/endpoint input (uri)
Attacks that exploit this kind of access
The rule that runs replace_image safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Mcp Google Docs, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For replace_image, this is the rule to start with:
replace_image stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Mcp Google Docs, apply this rule, and every replace_image call is checked against it from then on.
Questions about replace_image
Replaces an existing image's contents with a new image from a public URL, keeping the original's size and position (the new image is center-cropped to fit). image_object_id is the inline object id — read_document_text shows it inside [image:<objectId>] placeholders, and get_document lists all ids under inlineObjects. The same URL rules as insert_image apply (public, <=50 MB, <=25 MP, PNG/JPEG/GIF). It is categorised as a Write tool in the Mcp Google Docs MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
replace_image accepts 4 parameters: uri, tab_id, document_id, image_object_id. Required: uri, document_id, image_object_id. The full parameter table on this page comes from the server's own tool schema.
Register the Mcp Google Docs MCP server in PolicyLayer and add a rule for replace_image: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Mcp Google Docs. Nothing to install.
replace_image is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the replace_image rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for replace_image. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
replace_image is provided by the Mcp Google Docs MCP server (@a1-x-tech/mcp-google-docs). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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