link_figure_caption
[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 ...
This record as markdown: /tools/io-github-ajc3xc-meridian/link-figure-caption.md
What link_figure_caption does on Meridian
AI agents call link_figure_caption to permanently remove resources in Meridian, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
| 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.
Why link_figure_caption is rated Critical
An AI agent that decides to call link_figure_caption doesn't hesitate, doesn't double-check, and doesn't stop at one. Whatever it removes from Meridian is gone. There is no undo for destructive operations.
Attacks that exploit this kind of access
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 is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
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.
Questions about link_figure_caption
[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 -- including task log entries, pinned decisions, sprint items, notes, handoff/goal state, and HITL queue items -- are sent to and stored in Meridian's service, in an isolated per-tenant Postgres database (Neon); self-hosted deployments keep the same categories in the configured local SQLite/Postgres database. This data is visible in the dashboard and API, and may resurface in later project context or handoffs. Notes and pinned decisions can be deleted individually; task log entries and sprint items can be deleted via the dashboard/API (not exposed as an agent-facing tool); HITL queue items and handoff state have no per-record delete. Full removal of any of this data is available via project or account deletion, using the documented controls. Do not include secrets. It is categorised as a Destructive tool in the Meridian MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
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.
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.
link_figure_caption is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
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.
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.
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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