Install Hydrate.

Install

brew install getHydrate/hydrate/hydrate
hydrate doctor
hydrate install-hooks
hydrate doctor

Run hydrate doctor first to confirm the binary works, then hydrate install-hooks to wire the Claude Code hooks, then hydrate doctor again to verify the full setup.

What hydrate doctor checks

Seventeen checks. Exit code 0 means "Ready." This is the install gate, not marketing.

PreCompact and SessionStart together survive Claude Code's auto-compaction: when the context window fills, Hydrate writes a recovery snapshot before Claude compacts; the next session restores it automatically.

Output on a clean Free install:

claude
/hydrate-last

Paths show your real install locations (Homebrew default /opt/homebrew/bin/). The port after reachable is the live daemon port — 49849 is the default; a free-port hop is possible. hydrate doctor --json is available for scripts.

First run

Start a Claude Code session and rehydrate:

claude
/hydrate-last

/hydrate-last pulls the most recent distilled session for the current project. On a brand-new install there's nothing to rehydrate — that's expected. The Stop hook will start capturing facts from this session forward.

Verification

If hydrate doctor ends with Ready. and your first claude session prompts the UserPromptSubmit hook silently (no errors, no banner), you're done.

Configuring other agents

Hydrate ships a stdio MCP server (hydrate-mcp) alongside the main binary. Every MCP-capable client speaks to the same local Hydrate daemon. The load-bearing consequence: a fact you write from a Claude Code session is the same fact that surfaces from a Cursor or Codex hydrate_recall call ten minutes later — one local store, one canon, no extra account. The local API key in ~/.hydrate/api.key is read automatically; no PAT, no env var to set.

Note: Hydrate's UserPromptSubmit / Stop / PreCompact / SessionStart hooks are Claude Code only. From any other agent, the MCP tool surface (hydrate_recall, hydrate_canon_list, hydrate_facts_list, and the others) is what you reach for. Same memory, different read path.

{
  "mcpServers": {
    "hydrate": {
      "command": "hydrate-mcp"
    }
  }
}

[mcp_servers.hydrate]
command = "hydrate-mcp"
args = []

{
  "mcpServers": {
    "hydrate": {
      "command": "hydrate-mcp"
    }
  }
}

{
  "mcpServers": {
    "hydrate": {
      "command": "hydrate-mcp",
      "disabled": false,
      "autoApprove": []
    }
  }
}

{
  "mcpServers": {
    "hydrate": {
      "command": "hydrate-mcp"
    }
  }
}

{
  "context_servers": {
    "hydrate": {
      "command": {
        "path": "hydrate-mcp",
        "args": []
      }
    }
  }
}

All five clients run the same hydrate-mcp binary against the same local daemon. No account, no PAT, no per-tool credentials — the local API key in ~/.hydrate/api.key is read at spawn time. See /docs/integrations for the full integration matrix.

Privacy

• Local SQLite database by default
• Captured session summaries and extracted facts
• No cloud sync unless you enable it
• No raw transcript sharing in Hydration Packs
• Team memory is a git repo you control

Full privacy posture: see the privacy box on the homepage and /privacy.

Uninstall

hydrate uninstall-hooks

Your memory at ~/.hydrate/ is preserved and can be restored with hydrate install-hooks.

Troubleshooting

If hydrate doctor fails on a check, here's what it means:

hydrate binary installed

The hydrate CLI is not on your $PATH. Re-run brew install or check that /opt/homebrew/bin is on $PATH.

hydrate-server / hydrate-mcp binary installed

A companion binary is missing. brew reinstall hydrate puts them back.

~/.hydrate/ owned by current user

The data directory is owned by a different user (often root from an old sudo install). chown -R "$USER" ~/.hydrate.

~/.hydrate/data.db writable

The SQLite store can't be opened for writes. Check disk space and directory permissions.

local hydrate-server reachable

The background daemon is not running on its port. Run hydrate install-hooks again — it starts the server.

~/.hydrate/server.key present

The local API key is missing or has wrong permissions. Reinstall the hooks to regenerate it at mode 0600.

~/.claude.json parseable

Your Claude Code config has invalid JSON. Open it and fix the syntax, or delete it to let Claude Code regenerate.

UserPromptSubmit / Stop hook installed

The hook isn't wired into ~/.claude.json. Run hydrate install-hooks.

MCP server "hydrate" configured

The MCP server entry is missing from your Claude Code config. hydrate install-hooks writes it.

slash commands installed

/hydrate, /hydrate-last, /hydrate-project files aren't in ~/.claude/commands/. hydrate install-hooks installs them.

MCP reachable with configured api.key

The MCP server is configured but can't authenticate to the local daemon. Reinstall hooks to refresh the key.

License / License tier matches binary

Licence state on disk disagrees with the running binary. Re-run hydrate license activate or, for Free, hydrate install-hooks.