remove the get_host_journal MCP tool and its capability

swarm-logs covers every host-tier unit this tool could reach, so the
second, capability-gated path into host journald earns nothing and is
removed outright rather than disabled behind a flag.

Removed end to end: the MCP tool definition + handler, the
GetHostJournal/HostJournal wire variants, hive-c0re's
dispatch_host_journal handler, the ReadHostJournal capability, and the
harness-side capability->--allowedTools gate. get_host_journal was the
only capability that mapped to an MCP tool, so allowed_capability_tools
could only ever return an empty vec; it goes too rather than linger as a
function that provably does nothing.

capabilities::has_cap/caps_for stay: #4624 gave ManageRootAgent's
bind-mount enforcement (hive-c0re/src/lifecycle/host_config.rs) a
second caller of has_cap, so they're no longer callerless once this
lands on top of it.

hive-sh4re's journal module (JournalPriority) had no consumer outside
this tool and is deleted.

An existing capabilities.json still naming read_host_journal does not
error: capabilities::prune_unknown drops unrecognised names with a
warn!, and an agent left with no capabilities has its entry removed. No
migration step is needed.

Untouched: hive-c0re/src/dashboard/journal.rs's
read_host_journal_response, which matches the name but is the private
helper behind the operator-only GET /api/journal-host dashboard route
and carries no capability check.

docs/agent-lifecycle/persistence.md

@@ -399,7 +399,7 @@ Contents:
   `tool_groups::set_groups`; injected as `HIVE_TOOL_GROUPS` env
   var into each agent's container.
 - `capabilities.json` — per-agent capability grants
-  (`{ "atlas": ["read_host_journal"] }`). Written by
+  (`{ "ruth": ["manage_root_agent"] }`). Written by
   `capabilities::set_caps`; injected as `HIVE_CAPABILITIES` env
   var. Absent agents have no extra capabilities.
 - `resource-limits.json` — per-agent container resource overrides

docs/process/conventions.md

@@ -363,11 +363,10 @@ that allows the underlying resource access.
 | Capability | Effect |
 |---|---|
 | `manage_root_agent` | may manage *any* agent: bind-mounts every agent's state (rw) + config (ro) into the holder's container, plus `/applied` and `/meta` (ro). Takes effect on the holder's next container rebuild/restart |
-| `read_host_journal` | registers the `get_host_journal` MCP tool + serves `GET /journal-host` requests |
 
 **Config storage** — per-agent capabilities live in
 `/var/lib/hyperhive/meta/capabilities.json` alongside `tool-groups.json`.
-Format: `{ "atlas": ["read_host_journal"], "ruth": ["manage_root_agent"] }`.
+Format: `{ "ruth": ["manage_root_agent"] }`.
 An absent entry means "no extra capabilities." `render_flake` in `meta.rs`
 reads this file and injects `HIVE_CAPABILITIES` (comma-separated
 `snake_case` names) into each agent's systemd service env; absent entries emit

docs/tools/README.md

@@ -44,4 +44,4 @@ debug agent behavior.
   (`mcp__matrix__*`) for agents with a matrix account, multiple
   accounts per agent, and declaring extra MCP servers generally.
 - **[scheduling](scheduling.md)** — scheduled prompts (operator
-  approval required) and the `get_host_journal` diagnostics tool.
+  approval required).

docs/tools/scheduling.md

@@ -66,31 +66,6 @@ body, per-target `last_fired_at` and `last_result`,
 `next_fire_at_unix`, `interval_seconds`. Use to look up an id before
 cancelling, or to audit upcoming wake-ups across the hive.
 
-## `read_host_journal` capability
-
-Capability-gated (not a tool group) — the operator enables it in the
-P3RM1SS10NS C4P4B1L1T13S section. Unlike tool groups this isn't
-configurable from `agent.nix`.
-
-### `get_host_journal(unit?, container?, lines?, priority?, grep?, since?, until?)`
-
-Fetch recent lines from the **host** journal (requires
-`read_host_journal` capability). Useful when you need visibility
-outside your own container — infrastructure services, hive-c0re
-lifecycle events, or another container's boot log.
-
-- `unit` — filter to a systemd unit (for example `hive-c0re.service`).
-- `container` — nspawn machine name verbatim. Agent containers use
-  the `h-<name>` prefix (for example `h-iris`); infrastructure containers
-  use their full name (for example `hive-ci`, `hive-forge`, `hive-matrix`).
-  Omit for the host journal. The gateway has no machine — its nginx
-  runs on the host, so read it with `unit: nginx.service` and no
-  `container`.
-- `lines` — how many lines to return (default 30, max 100).
-- `priority` — minimum syslog level (`emerg` … `debug`).
-- `grep` — regex matched against log message fields (`journalctl --grep`).
-- `since` / `until` — time bounds (for example `-1h`, `2024-01-01 12:00:00`).
-
 ## See also
 
 - `remind` (no-approval self-wake path) — documented in

docs/turn-loop/mcp.md

@@ -150,11 +150,10 @@ hive_name?, swarm_name?, matrix_accounts? }`. `matrix_accounts` is a
   and `WebSearch` tools (not MCP tools; added directly to the
   `--allowedTools` list). Off by default; add the group in the
   P3RM1SS10NS tab and rebuild to enable.
-- **Capability-gated** — `get_host_journal` (requires
-  `read_host_journal` capability set via the P3RM1SS10NS tab;
-  orthogonal to tool groups). Full list of capabilities and their
-  effects in [`docs/process/conventions.md#capabilities`](../process/conventions.md).
-  Also documented in [`docs/tools/scheduling.md`](../tools/scheduling.md).
+- **Capabilities** — orthogonal to tool groups, set via the P3RM1SS10NS
+  tab. No capability registers an MCP tool today; the full list and their
+  effects are in
+  [`docs/process/conventions.md#capabilities`](../process/conventions.md).
 - **Matrix MCP + extra servers** — `mcp__matrix__*` tools and
   per-agent extra MCP config. See
   [`docs/tools/matrix.md`](../tools/matrix.md).

docs/web-ui/dashboard.md

@@ -441,7 +441,6 @@ The current capabilities are:
 | Name | Effect |
 |------|--------|
 | `manage_root_agent` | mounts every agent's state (rw) + config (ro) into this agent's container so it can manage/recover any agent |
-| `read_host_journal` | unlocks `get_host_journal` to read journald from inside a container |
 
 Each row is one agent. Columns are the capability names returned by
 `GET /api/capabilities` as `caps: Vec<String>`. Checking or unchecking