--- title: "Cork vs Mosaic: shared session memory, or live coordination on the code · Cork" description: "Cork vs Mosaic: Mosaic syncs AI coding sessions into shared team memory; Cork keeps parallel agents from overwriting each other. How they differ and fit." canonical: "https://corkcli.com/blog/cork-vs-mosaic" last_updated: "2026-11-14" published: "2026-10-03" author: "Kevin Vera" --- # Cork vs Mosaic: shared session memory, or live coordination on the code Cork vs Mosaic: Mosaic syncs AI coding sessions into shared team memory; Cork keeps parallel agents from overwriting each other. How they differ and fit. By Kevin Vera · October 3, 2026 · [Comparisons](https://corkcli.com/blog/c/comparisons) · 7 min read How is Cork different from Mosaic? Mosaic and Cork both start from the same observation: once a team runs several coding agents, what one agent learns is trapped in its own session. Mosaic answers it by syncing everyone's AI coding sessions (Claude Code, Codex, Cursor) into one shared memory that any agent can draw on later. Cork answers it at the moment of editing: it tells each agent who is changing the code it is about to touch, holds writes that would overwrite a teammate's live change, and briefs the agent with the exact signatures and callers before it starts. Put simply, Mosaic preserves the history of what agents did; Cork coordinates what parallel agents are doing right now. ## Cork vs Mosaic at a glance | Topic | Cork | Mosaic (as of October 2026) | |---|---|---| | What it is | [Coordination layer](https://corkcli.com/blog/coordination-layer-ai-coding-agents) for parallel AI coding agents on one codebase | Shared memory of team coding-agent sessions ("Everyone's AI coding sessions, in one place") | | Where agents run | Where they already run, on your machine | Where they already run; Mosaic keeps a background-synced local replica at `~/.mosaic` | | Agents covered | Claude Code, Codex, Cursor (hooks), plus any MCP client | Named in its docs: Claude Code, Codex, Cursor | | What is shared | Live edits, signatures, callers, recent changes, notes anchored to code | Coding-agent sessions, so agents can see what happened and why | | Conflict handling | Write gate holds edits against code another agent is changing; [semantic lint](https://corkcli.com/blog/semantic-lint) for renames | Not described on its site; we could not verify any conflict handling | | Install | `curl -fsSL https://corkcli.com/install.sh \| sh` | `brew install emergent-inc/tap/mosaic && mosaic install` | | Integration style | Hooks plus an MCP server | Background service plus instruction-only skill files in supported agents | | Pricing | Free (local, and 10 agent hours a month in the cloud); $20 a month per 100 agent hours, pooled; Enterprise custom | We could not verify published pricing | ## What is Mosaic? Mosaic is a Y Combinator Summer 2026 company. Its YC profile says Mosaic "synchronizes AI coding sessions from Claude Code, Codex, Cursor, and other tools into a centralized repository that any agent can access," so agents stop starting every session from zero context. Its homepage tagline is "Everyone's AI coding sessions, in one place." Its install guide describes what gets set up on a Mac: a CLI, a background service, and "a background-synchronized local replica of team coding-agent sessions at `~/.mosaic`." It prompts before installing "instruction-only skill files" into supported agents' skill directories. The guide also states that Mosaic "does not collect product telemetry." We could not find published pricing or an open source license. ## What is Cork? Cork (corkcli.com, by Lithometric) keeps several AI coding agents, and the people running them, from overwriting each other on one codebase, and hands each agent what the others already learned. It does not run agents or host machines; your Claude Code, Codex and Cursor agents keep running where they already run. Hooks in Claude Code, Codex and Cursor run the protocol with no extra model calls, and an MCP server (https://mcp.corkcli.com) serves any MCP client. In practice: - **Briefing:** on start and on each prompt, the agent gets the exact signatures, callers and recent changes of the code it is about to touch, so it searches less. - **Live awareness:** when another agent renames or re-signatures code yours depends on, your agent hears it on its next step. - **[Write gate](https://corkcli.com/blog/write-gate):** an edit against code another agent is changing right now is held until your agent has their version. - **Semantic lint:** a teammate's rename or signature change becomes a lint rule your agents are checked against. - **Landing:** `git push` becomes one step that rebases onto teammates' commits, reruns the tests and pushes. - **Agent messaging** to the whole repo, one agent, or whoever is working on a given function, and MCP tools such as get_symbol, blast_radius, recap and remember/recall. ## Where Mosaic stands out - **Cross-session continuity.** Its core job is making past sessions, decisions and dead ends available to the next person or agent, across tools. - **Tool-agnostic history.** Sessions from Claude Code, Codex and Cursor land in the same place, which suits teams that mix agents. - **Local replica.** The synced sessions live on each machine at `~/.mosaic`, so agents can read them without a round trip. - **Light touch.** Its integration is a background service plus instruction-only skill files, with no telemetry according to its install guide. ## Where Cork wins - **Prevents overwrites instead of recording them.** The write gate holds an edit against code a teammate's agent is changing right now; remembering a session after the fact cannot stop two [parallel AI coding agents](https://corkcli.com/blog/parallel-ai-coding-agents) from clobbering the same function. - **Code-level facts, not transcripts.** Briefings carry exact signatures, callers and recent changes for the symbols in play, rather than conversation history an agent has to interpret. - **Catches breaking changes.** Semantic lint turns a teammate's rename or new signature into a check your agents run against, which addresses agent merge conflicts before they reach a PR. - **Measured token savings.** In Cork's benchmark (12 Claude Code agents at once on one repository, hard tasks), agents with Cork used 53% fewer tokens than the same agents without it. - **Published pricing and a free local mode.** Cork Free runs on one machine with no account and keeps all data there. ## Can you use both? Yes, and they overlap less than the "shared memory" label suggests. Mosaic is strongest at the question "what did someone's agent figure out last week?" Cork is strongest at "who is editing this right now, and what does my agent need to know before it writes?" A team running multiple Claude Code agents alongside Codex could let Mosaic carry session history between people and let Cork gate writes and brief agents on the live code. Cork's remember/recall notes also cover durable decisions anchored to specific code, so if that is all you want from shared memory, you may not need both. ## Pricing compared Cork Free covers unlimited agents and repos on one machine with no account. Cloud Free adds an account with 10 agent hours a month (30 bonus hours the first month) and a 30-day history window. Beyond that you pay for agent hours, not seats: $20 a month per unit of 100 hours, pooled across the workspace, graduated to $17 (units 11 to 50) and $15 (51 and up), with 15% off a year. Every member is a player, with teammates' machines, prompts matched to code by meaning, shared knowledge and 90-day history. Enterprise starts from about 100 units. For Mosaic, we could not verify published pricing as of October 2026. ## Bottom line Mosaic is a shared memory of coding-agent sessions: useful when the pain is rediscovery and handoffs across people and tools. Cork is a coordination layer for [multiplayer coding agents](https://corkcli.com/blog/multiplayer-coding-agents): useful when the pain is parallel agents editing the same code and breaking each other. If your agents keep overwriting each other, Mosaic does not claim to solve that and Cork does. If your agents keep forgetting what a colleague's session learned, Mosaic is built for exactly that. ## Frequently asked questions ### Is Cork an alternative to Mosaic? Partly. Both help agents arrive informed, but Mosaic shares session history while Cork coordinates live edits and briefs agents on the code itself. Teams that mainly need to stop agent merge conflicts will find Cork the closer fit. ### Does Mosaic stop agents from overwriting each other? Its site and install guide describe session syncing, not edit coordination. We could not verify any feature that holds or blocks conflicting writes as of October 2026. ### Which coding agents do Mosaic and Cork support? Mosaic's docs name Claude Code, Codex and Cursor. Cork has hooks for Claude Code, Codex and Cursor and an MCP server that any MCP client can use. ### Does Cork store my agents' conversations? Cork's facts are about code: signatures, callers, recent changes, and notes your agents choose to remember. With Cork Free, all data stays on your machine. ### Can I run multiple Claude Code agents with Cork and Mosaic together? Yes. Neither runs your agents; both sit alongside Claude Code where it already runs. ## Sources Checked October 2026: - - - - ## Related reading - [Cork vs HumanLayer: an agent IDE for teams, or coordination under any tool](https://corkcli.com/blog/cork-vs-humanlayer): Cork vs HumanLayer: HumanLayer is a multiplayer coding agent IDE and cloud; Cork keeps parallel agents from overwriting each other wherever they run. - [Cork vs qm: a team agent harness, or a coordination layer for coding agents](https://corkcli.com/blog/cork-vs-qm): Cork vs qm: YC's open source qm is a multiplayer agent harness for Slack and web. Cork keeps parallel AI coding agents from overwriting each other's code. - [Cork vs Herdr: where agents live vs how they share a codebase](https://corkcli.com/blog/cork-vs-herdr): Cork vs Herdr: Herdr keeps AI coding agents running in persistent terminal panes. Cork keeps those parallel agents from overwriting each other's code. - [Cork vs Amika: VMs for your agents, or coordination between them](https://corkcli.com/blog/cork-vs-amika): Cork vs Amika: Amika provisions multiplayer VM Rigs for coding agents. Cork keeps parallel agents on one codebase from overwriting each other. [All articles](https://corkcli.com/blog.md) · [Cork in Markdown](https://corkcli.com/index.md) · [llms.txt](https://corkcli.com/llms.txt) This page in HTML: https://corkcli.com/blog/cork-vs-mosaic