Four diff scopes keep agent changes separate
herdr-reviewr gives a Herdr workspace 4 useful ways to inspect code: uncommitted changes, the whole branch, the most recent agent turn, and a chosen run of commits. The distinction matters when an agent commits as it works or when your own edits share the same worktree. A reviewer can move between changed files, jump by hunk, select a line range, write comments, and send the complete batch back to the agent pane. The worktree itself stays untouched.
The pane browses current files, searches filenames and code, previews Markdown, and mirrors an open pull request. Its PR view is read-only and covers GitHub, GitLab, and Azure DevOps through authenticated command-line clients. It also has 18 palettes and mouse selection. This is a focused review surface rather than a full Git client.
Herdr 0.7.5 unlocks sending and last-turn review
The shortest installation uses Herdr 0.7.5 or newer to fetch a prebuilt plugin binary. Git, a truecolor terminal, Unicode box-drawing characters, and either macOS or Linux are required. Opening the plugin beside an agent then gives Send and the last-turn scope. The default configuration auto-opens it for worktree workspaces, though that can be disabled in the plugin's own TOML file.
A downloaded release binary also runs as a plain terminal application against a repository path. In that mode, browsing, diffs, search, comments, and PR reading remain available, but comments cannot be sent to an agent and the last-turn boundary is unknown. The PR tab needs gh, glab, or az, depending on the forge. Self-hosted instances require an exact hostname in configuration, while unsupported forges get no PR view.
Source builds pin Rust 1.97.0 and use just. The documented CI command checks formatting, rejects Clippy warnings, runs tests, and makes a release build. Our checkout had 3 workflow files, including a weekly dependency-policy job, but no Dockerfile. Container users must supply the build environment.
What happened when we ran it
Our sandbox installed 242 Rust packages in 33 seconds, then completed the build in 181 seconds. The checkout at commit 4c09022 contained 86 files, about 43,892 source lines, and occupied 2.4 MB before dependencies. Installation and compilation both returned success in the unprivileged Debian container with 3 CPUs and 12 GB of RAM.
The full test command returned exit code 101 after 94 seconds. Across the run, 1,284 tests passed and 46 failed out of 1,330. The final pane_actions binary reported 6 passes and 23 failures. Names visible at the end covered fresh-tab naming, a silent runtime-refusal case, and forwarding non-default placement and direction to Herdr arguments. The supplied tail contains no assertion detail or common root cause, so it would be wrong to blame a missing package or a Herdr version from that evidence alone.
Draft comments vanish, and Send can hit a busy pane
Comments last for one pane session. Closing reviewr loses anything unsent or uncopied. Send delivers the whole set and clears it on success, while a reported failure retains the batch. Comments do not rebase as lines move; reviewr marks an anchor stale when it cannot locate the captured snippet. Use a forge when review history must persist.
Open issue 86 describes a sharper failure. When the destination agent is working or stopped at a permission prompt, the submitted text can land on the current interface rather than becoming a new agent turn. The report says feedback may be swallowed, appended to a prompt, or executed later in the wrong context. Until that path is fixed and released, wait for an idle agent and keep a clipboard copy of any consequential review batch.
Remote use has another concrete snag. Issue 95 reports that pressing o in Herdr remote mode runs xdg-open on the Ubuntu server instead of the user's machine. The PR remains readable inside the pane, so this does not break local diff review. It does remove the expected browser handoff for anyone operating Herdr on a headless host.
A 2-second poll and terminal limits narrow the fit
The default refresh interval is 2,000 ms, with 200 ms as the minimum. Issue 63 reports repeated Git operations that walk a large worktree while the pane is idle. The report is not our lab timing, but large-repository users should test it before leaving several panes open. A longer interval trades lower activity for later updates.
Rendering also has firm boundaries. Files above 2 MB or 50,000 lines display a size notice, and binary files get no text diff. Truecolor has no lower-color fallback. Added and removed lines use red and green without a second colorblind cue, while light or dark theme selection is manual. Clipboard export calls pbcopy, wl-copy, xclip, or xsel; Send still works if none is installed.
September issue activity is faster than the release cadence
GitHub recorded 656 stars and 33 open issues and pull requests, with the last source push on September 5, 2026. New issue activity continued on September 10, including a request for image previews. Release v0.36.2 was published on August 29 and fixed auto-opening when an existing checkout receives a new Herdr workspace. The recent push plus current reports point to active development, while the combined open count should not be read as 33 confirmed bugs.
Changes are expected to update a dated behavior specification and the changelog. Performance work also calls for before-and-after terminal latency measurements. Those practices are encouraging, but the 46 failed tests and open Send bug still decide the production case. Interactive Herdr users can try the prebuilt plugin; durable review delivery belongs in a forge.