link_figure_caption

SERVERMeridian SOURCE@meridianmcp/mcp

Medium RISK CLASS

Category Write

Parameters 53 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-ajc3xc-meridian/link-figure-caption.md

WHAT IT DOES

What link_figure_caption does on Meridian

AI agents use link_figure_caption to create or update resources in Meridian, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Meridian environment.

Parameter	Type	Required	Description
`doc`	string	Yes	The stored document's source (the path/URL you ingested it under via ingest_document).
`figure_id`	string	Yes	The doc_figures.id of the figure row to update (from index_figure or find_similar_figure).
`project_id`	string	—
`project_name`	string	—	Project name — an alternative to project_id; resolved to the id internally. project_id wins if both are given.
`caption_element_id`	string	Yes	The doc_elements.id of the caption paragraph to durably link to this figure.

Parameters from the server's own tool schema.

RISK

Why link_figure_caption is rated Medium

This tool creates/updates a persistent association between two existing database records (doc_figures and doc_elements). It is a write operation that modifies stored metadata by linking a figure to its caption element. It is reversible in principle (the link could be updated or removed), not destructive, and has no financial or execution implications.

From the tool's definition DURABLY link an already-indexed figure (doc_figures row) to its caption paragraph... to confirm an advisory suggested_caption_element_id... or to backfill a durable link

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs link_figure_caption safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Meridian, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For link_figure_caption, this is the rule to start with:

link_figure_caption Rate-limited

link_figure_caption 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "link_figure_caption": {
      "limits": [
        {
          "counter": "link_figure_caption_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Meridian, apply this rule, and every link_figure_caption call is checked against it from then on.

FAQ

Questions about link_figure_caption

What does the link_figure_caption tool do? +

[MAINTENANCE] 0ff8b982 — DURABLY link an already-indexed figure (doc_figures row) to its caption paragraph (a doc_elements id), by stable structural id rather than paragraph proximity. Use this to confirm an advisory suggested_caption_element_id returned by index_figure, or to backfill a durable link on a figure that was indexed before caption linkage was supported. Provide figure_id (the doc_figures.id of the figure to link) and caption_element_id (the doc_elements.id of the caption paragraph — a kind='figure' SEQ-field element from the section-tree store). This is the confirmation primitive for the 'Figure 3b used twice' ambiguity scenario: when index_figure surfaces suggested_caption_candidates (multiple captions in the same section), inspect them and call this tool with the correct one to confirm the durable link. Returns the updated figure row on success, or {error} when figure_id doesn't resolve to a known figure. Persistent-state disclosure: on hosted Meridian, supplied text and project/session metadata are sent to and stored in Meridian's service; self-hosted deployments keep them in the configured local SQLite/Postgres database. This data is visible in the dashboard/API and later project context or handoffs. Delete individual tasks, notes, or decisions where supported, or delete the project/account using the documented controls. Do not include secrets. It is categorised as a Write tool in the Meridian MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does link_figure_caption accept? +

link_figure_caption accepts 5 parameters: doc, figure_id, project_id, project_name, caption_element_id. Required: doc, figure_id, caption_element_id. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on link_figure_caption? +

Register the Meridian MCP server in PolicyLayer and add a rule for link_figure_caption: 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 Meridian. Nothing to install.

What risk level is link_figure_caption? +

link_figure_caption is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit link_figure_caption? +

Yes. Add a rate_limit block to the link_figure_caption 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.

How do I block link_figure_caption completely? +

Set action: deny in the PolicyLayer policy for link_figure_caption. 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.

What MCP server provides link_figure_caption? +

link_figure_caption is provided by the Meridian MCP server (@meridianmcp/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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