Skills Artificial Intelligence Semantic Memory for AI Agents

Semantic Memory for AI Agents

v20260526
mesh-memory
A self-hosted, semantic memory service designed for AI agents. It allows agents to save worklogs, decisions, and notes, and recall this knowledge across sessions based on meaning rather than exact keywords. Using pgvector and structured workspaces, it maintains persistent, context-aware knowledge bases, making it ideal for collaborative AI projects.
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Overview

Mesh Memory

Mesh Memory is a self-hosted semantic memory service with a built-in MCP server. It stores documents (worklogs, decisions, notes, research) in PostgreSQL with pgvector and retrieves them by meaning, so a query like "what database did we pick?" surfaces a saved note that says "chose Redis for caching" even with zero keyword overlap. Embeddings are generated locally with multilingual-e5-base (768 dimensions); the core flow requires no external API keys.

Use this skill when an agent needs persistent memory across sessions: saving its own work, recalling prior decisions, or building a project knowledge base shared between multiple agents.

When to Use This Skill

  • Saving a session worklog, decision, or research note so a later session can find it.
  • Recalling past work by topic when you do not remember the exact words you used.
  • Sharing a long-lived knowledge base across multiple agents, terminals, or teammates.
  • Organizing context by role or project through workspaces (one workspace per role/project).
  • Looking up structured tags (e.g. all type:decision entries from one project).

Prerequisites

  • A running Mesh Memory instance reachable from the MCP server. Local Docker is the common path -- docker compose up -d in the upstream repo brings it up; see https://github.com/dklymentiev/mesh-memory for the full Quick Start.
  • The MCP server (mcp_server.py) registered with your client (Claude Code, Cursor, Claude Desktop, or any other MCP-aware agent).
  • MESH_API_URL pointing at the running instance (default: http://localhost:8000).

Setup

Register the MCP server in your client configuration:

{
  "mcpServers": {
    "mesh": {
      "command": "python3",
      "args": ["/path/to/mesh-memory/mcp_server.py"],
      "env": {
        "MESH_API_URL": "http://localhost:8000"
      }
    }
  }
}

When the server is reachable, the 13 tools listed below become available.

MCP Tools

Tool Purpose
mesh_focus Switch the active workspace (optionally prefetch recent docs).
mesh_add Save a document with optional tags. Auto-adds date:YYYY-MM-DD and source:.
mesh_update Update content, tags, or pinned status of an existing document.
mesh_delete Delete a document by GUID.
mesh_get Fetch a single document by GUID.
mesh_search Semantic search by query, optionally across multiple workspaces with weights.
mesh_bytag List documents that match one or more tags (AND logic).
mesh_recent List most recently created documents, optionally filtered by type: tag.
mesh_projects List per-project document counts (uses guid: tag as project marker).
mesh_tags List existing tags with counts; optional prefix filter.
mesh_versions Show the version chain of a document (similarity-linked revisions).
mesh_stats Memory statistics for the active workspace.
mesh_schema Show the tag schema (recognized prefixes and types).

Workflows

Save a session worklog

After completing work, persist it for future sessions:

mesh_add(
  content="Investigated 502s on the checkout flow. Root cause: missing CORS header on the cart API. Fix shipped in commit abc123.",
  tags="type:worklog,topic:checkout,date:2026-05-23",
  workspace="developer"
)

date: and source: are added automatically when omitted. Type and topic tags are inferred from nearest neighbors after the embedding completes (5-10 seed documents required before inference kicks in).

Recall past work by meaning

Search across sessions for related context, even with different vocabulary:

mesh_search(query="checkout was failing for some users", limit=5, workspace="developer")

The query shares no keywords with the original note ("502s", "CORS"), but the embedding-based search surfaces it.

Switch role / context

For a multi-role agent, switch the active workspace at the start of a session:

mesh_focus(workspace="sysadmin", prefetch=true, limit=5)

Subsequent calls default to that workspace. Pin a role-prompt document at the top of each workspace so the agent re-orients on every prefetch.

Cross-workspace search with weights

To pull context from related domains without diluting the primary signal:

mesh_search(
  query="nginx rate limit recipe",
  workspaces={"sysadmin": 0.7, "security": 0.2, "developer": 0.1},
  limit=10
)

Results are merged across workspaces and re-scored by workspace weight.

Structured lookups by tag

When you need an exact filter rather than semantic similarity:

mesh_bytag(tags="type:decision,status:active,guid:my-project", limit=20)

Tag Conventions

Mesh accepts arbitrary tags. The recommended prefixes (used by auto-inference and surfaced by mesh_schema):

Prefix Meaning
type:worklog Completed work; the most common type.
type:note Quick notes, observations.
type:decision Architecture or product decisions.
type:research Investigation results, findings.
type:task Action items.
type:rfc Proposals for review.
status:active / status:completed / status:archived Lifecycle.
date:YYYY-MM-DD When the document was created (auto-added).
source: How the document arrived (auto-added: mcp, api, etc.).
guid:<project-id> Project marker -- use a consistent slug across all docs of a project.

With fewer than ~5-10 documents in a workspace, neighbor inference is skipped; manually tag seed documents until the corpus self-organizes.

Troubleshooting

Tool calls fail with connection errors. The MCP server cannot reach MESH_API_URL. Verify the instance is up (curl $MESH_API_URL/health returns {"status":"healthy"}) and the env var is set in the MCP config.

A saved document does not appear in semantic search yet. Embedding generation runs in the background. After a save, expect a 1-2 second delay before semantic search hits the new document. mesh_get(guid=...) confirms the document exists immediately.

Search returns results from the wrong domain. The active workspace is not what you expected. Call mesh_focus(workspace="<name>") explicitly, or pass workspace= on every call. With no focus and no explicit param, calls land in the default workspace.

Auto-tagging never adds anything. The workspace has too few documents for neighbor inference (~5-10 minimum). Manually tag a handful of seed documents, then auto-inference takes over.

A deleted document still appears in a search result. Embedding indices are eventually consistent; rerun the search after a few seconds, or use mesh_get(guid=...) to confirm deletion.

Limitations

  • Mesh is a knowledge store, not a chat memory. Long conversation transcripts should be summarized before being saved.
  • Vector similarity is robust but not perfect; for high-precision structured lookups, prefer mesh_bytag over mesh_search.
  • Embeddings run on CPU by default; very large corpora (hundreds of thousands of documents) benefit from a dedicated instance and pgvector tuning, not covered here.
  • The optional AI categorizer requires an OpenAI-compatible LLM endpoint and is disabled by default.
Info
Name mesh-memory
Version v20260526
Size 7.39KB
Updated At 2026-06-02
Language