Memo Update Tools are a 📝MythOS MCP capability for editing an existing memo at three granularities — the whole 📝memo, a single section, or a single line or list-item — so an AI agent can make a precise change without re-sending the entire memo.

They exist because re-emitting a long memo by hand to change one paragraph risks transcription drift and formatting corruption; the finer-grained tools let an agent touch only what changes while every byte outside the edit is preserved verbatim.

They serve AI agents and developers working through the MythOS MCP — Claude, Cursor, and any MCP-compatible client — on Scholar and Oracle plans, and are most valuable for maintaining long, frequently-edited memos like roadmaps and reference docs.

Key Capabilities

• Full update (update_memo) — replaces a memo's content, title, tags, notes, visibility, and SEO fields in one call. Live today.
• Section update (update_memo_section) — edits one section addressed by its heading: replace the section body, insert just below the heading, or append to the end of the section, leaving every byte outside the section untouched. Rolling out to production.
• Line update (update_memo_line) — edits a single line or list-item located by a unique text anchor: replace it, delete it, or insert a new line before or after it. It is list-aware, so deleting a parent bullet takes its indented sub-items with it rather than orphaning them. Rolling out to production.
• Optimistic locking — every update requires an expectedUpdatedAt token from a prior read, so a stale edit is rejected rather than silently clobbering a concurrent change.
• Save-parity side effects — all three run the same pipeline as a UI save: tag re-extraction, mention and reference rebuilding, snippet regeneration, and RAG re-embedding.

Getting Started

1. Connect the MythOS MCP to your client and generate an API key at mythos.one/settings/api-keys (Scholar or Oracle tier).
1. Call read_memo for the target memo and note its current updatedAt.
1. Pick the granularity: update_memo for a full rewrite, update_memo_section to change one section by its heading, or update_memo_line to change one line or list-item by a unique anchor.
1. Pass the updatedAt you read back as expectedUpdatedAt so the edit is concurrency-safe; the server applies the change and re-runs every save side effect automatically.

Related

• 📝MythOS — the platform
• 📝MythOS MCP — the MCP surface these tools join
• 📝MythOS MCP Tools — the complete tool reference with parameters and annotations

Contexts

• 🏷️#mythos
• 🏷️#mythos-feature