index_equation
[MAINTENANCE] 06df6ab3 — index ONE Word equation (OMML) against a document already stored in the doc-structure store — populated by ingest_document (which registers a docx/latex document's structure here in addition to storing the flat note text). Pass the SAME source/path you ingested under as d...
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What index_equation does on Meridian
AI agents use index_equation 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, which registers a docx/latex document in the doc-structure store). |
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. |
omml_or_latex | string | Yes | Raw OMML XML (starts with '<') OR a LaTeX source string. |
semantic_label | string | — | Optional human label for the equation (e.g. 'mass-energy equivalence'). |
Parameters from the server's own tool schema.
Why index_equation is rated Medium
This tool writes/indexes an equation into an existing document structure store. It creates or modifies stored data (adding an equation index entry) but does not irreversibly delete data, execute code, or involve financial operations. The operation is a structured write to a persistent store, making Write the appropriate category.
From the tool's definition index ONE Word equation (OMML) against a document already stored in the doc-structure store — populated by ingest_document
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
The rule that runs index_equation 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 index_equation, this is the rule to start with:
index_equation 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 Meridian, apply this rule, and every index_equation call is checked against it from then on.
Questions about index_equation
[MAINTENANCE] 06df6ab3 — index ONE Word equation (OMML) against a document already stored in the doc-structure store — populated by ingest_document (which registers a docx/latex document's structure here in addition to storing the flat note text). Pass the SAME source/path you ingested under as doc. omml_or_latex is auto-detected: a string starting with '<' is treated as raw OMML XML (stored as-is); anything else is treated as LaTeX source (real OMML is generated best-effort — pure-Python latex2mathml piped through a hand-written MathML->OOXML mapper; returns null omml on an unsupported construct, never an error). Before inserting, the normalized LaTeX is fuzzy-matched against every equation already stored for this document — a near-duplicate is NOT silently dropped (the equation is still inserted) but IS surfaced via near_duplicates:[{equation_id, matched_id, matched_latex, score}] so you can spot accidental re-derivations. Returns {equation, near_duplicates}. 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.
index_equation accepts 5 parameters: doc, project_id, project_name, omml_or_latex, semantic_label. Required: doc, omml_or_latex. 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 index_equation: 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.
index_equation 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 index_equation 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 index_equation. 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.
index_equation 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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