annotate_outputs
[SUPPORT] 9e02e448 — capture a human annotation for a path inside an outputs tree WITHOUT touching the filesystem. Upserts a row into the annotations layer of the local DuckDB outputs index for outputs_dir. Two tiers, same mechanism: Tier 1 = pass outputs_dir as path to annotate the whole tree ('...
This record as markdown: /tools/io-github-ajc3xc-meridian/annotate-outputs.md
What annotate_outputs does on Meridian
AI agents use annotate_outputs 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 |
|---|---|---|---|
note | string | Yes | The annotation text (e.g. 'PCA on, BFS off — results from run on 2026-07-12 with lr=0.001'). |
path | string | Yes | The path to annotate — either the outputs_dir root (Tier 1, tree-level annotation) or any file/subdirectory path within the tree (Tier 2, per-run or per-file an |
run_params | object | — | Optional free-form key-value dict of run parameters to log alongside the note (e.g. {"lr": 0.001, "epochs": 100}). |
outputs_dir | string | Yes | Absolute path to the outputs directory tree root (same value you pass to search_outputs). |
Parameters from the server's own tool schema.
Why annotate_outputs is rated Medium
This is a metadata annotation tool that creates or modifies records in a local DuckDB index. It is a Write operation because it performs upserts (insert/update) on database rows. It is not Destructive because upserts are reversible—subsequent calls can overwrite previous annotations.
From the tool's definition Tool description states it "Upserts a row into the annotations layer" of a local database index. Upsert is a write operation (insert or update).
Risk signalsAccepts file system path (path)
Attacks that exploit this kind of access
The rule that runs annotate_outputs 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 annotate_outputs, this is the rule to start with:
annotate_outputs 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 annotate_outputs call is checked against it from then on.
Questions about annotate_outputs
[SUPPORT] 9e02e448 — capture a human annotation for a path inside an outputs tree WITHOUT touching the filesystem. Upserts a row into the annotations layer of the local DuckDB outputs index for outputs_dir. Two tiers, same mechanism: Tier 1 = pass outputs_dir as path to annotate the whole tree ('what this experiment tree is about'); Tier 2 = pass any sub-path (file or directory) to annotate a specific run, file, or subdirectory ('PCA on, BFS off, overwritten 5x'). run_params is an optional free-form dict of parameters logged alongside the note (e.g. {"lr": 0.001, "batch_size": 32}). Annotations are automatically surfaced in search_outputs results — any hit's path (or its nearest ancestor directory) that has an annotation will have it included in the hit's 'annotations' field without a second tool call. A MERIDIAN_NOTES.md file placed anywhere in the tree is also auto-ingested into the same table on every rebuild, keyed to its containing directory. Returns the stored annotation as a dict. 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.
annotate_outputs accepts 4 parameters: note, path, run_params, outputs_dir. Required: note, path, outputs_dir. 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 annotate_outputs: 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.
annotate_outputs 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 annotate_outputs 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 annotate_outputs. 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.
annotate_outputs 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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