# Session Name > Assign or update a short label describing what this Claude Code session is currently doing, stored in a per-session sidecar file so status_line.sh and the tab title can show it - Skill: `yonichechik/session-name` (Agent Skill) - Install (CLI): `npx skillmds add yonichechik/session-name` - Raw SKILL.md: https://api.skillmd.com/api/skills/yonichechik/session-name/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: YoniChechik (https://skillmd.com/u/yonichechik) - Updated: 2026-09-10 - Page: https://skillmd.com/skills/yonichechik/session-name --- Sets (or re-sets) the current session's display name: a short, human-readable label stored in a per-session sidecar file. `status_line.sh` and the tab-title mechanism read only this file — there is no fallback to the branch/worktree name or to Claude Code's own native `session_name` field. Safe to re-run any number of times in one session as the topic drifts; each run is a fresh decision, not a one-time setup step. ## Step 1: Guard the session id ```bash if [[ -z "${CLAUDE_CODE_SESSION_ID:-}" ]]; then echo "Error: CLAUDE_CODE_SESSION_ID is unset; cannot set a session name." >&2 exit 1 fi ``` Every file this skill touches is keyed on this exact env var, matching the convention `ci-watcher` and `_notify.sh` already use for their own `/tmp/*_` files. ## Step 2: Load the shared helpers and read the currently-stored name `scripts/_notify.sh` holds the ONE implementation of this feature's sanitize-and-cap contract. Source it and use it — never re-inline a copy of the sanitize logic here, in `status_line.sh`, or anywhere else. ```bash source ~/.claude/scripts/_notify.sh STORED_NAME=$(_session_name_read "$CLAUDE_CODE_SESSION_ID") ``` `_session_name_read` returns the stored name already sanitized and capped, and returns empty for every "no usable name" case: missing file, empty file, a non-regular file, or content that sanitizes down to nothing. ## Step 3: The sanitize-and-cap contract `_sanitize_and_cap ""` (from the same sourced file) is the one contract every read site and write site shares. It: - Strips C0 control bytes (`0x00-0x1F`, which covers raw ESC, BEL, newline and tab), DEL (`0x7F`), and C1 (`0x80-0x9F`). - Strips the backslash character. Raw control bytes are not the only threat: any renderer that expands backslash escapes turns purely-printable text like `\033]0;PWNED\007` back into a genuine terminal escape sequence, so the backslash is removed at the source. - Drops invalid UTF-8 bytes instead of crashing on them. - Trims leading and trailing whitespace. - Caps at 35 Unicode **codepoints** — never a bash byte-slice like `${name:0:35}`, which can split a multi-byte UTF-8 character mid-sequence. Run every candidate name — forced argument or auto-proposed — through it before comparing or writing. ## Step 4: Determine the proposed name - If `$ARGUMENTS` is non-empty, sanitize+cap it (Step 3) — this is the proposed name, forced by the caller. No exemption from sanitize/cap rules just because it was explicitly given. - Otherwise, look at the current conversation, branch name, and task at hand, and decide a short (aim well under 35 codepoints) label that describes what this session is currently doing. Sanitize+cap it the same way (Step 3) even though it's model-generated — the cap and strip rules apply universally, not only to user-supplied text. If the sanitized proposed name is **empty** (an all-whitespace, all-control-byte or all-backslash candidate), stop here: report the error to the user and write nothing. An empty sidecar means "no name" to both readers, so writing one would silently clear the status-line segment and blank the tab title instead of naming the session. ```bash if [[ -z "$PROPOSED_NAME" ]]; then echo "Error: the proposed session name is empty after sanitizing; nothing written." >&2 exit 1 fi ``` ## Step 5: No-op check Compare the sanitized proposed name (Step 4) to the stored name (Step 2, which is already sanitized). If they are identical: - Make **no write**. Do not touch the sidecar file, do not re-emit the title escape. - Tell the user the current session name still fits and stop here. This is a first-class, correct outcome — renaming is not mandatory just because this skill ran. Otherwise, continue to Step 6. ## Step 6: Mandatory orchestrator confirmation (subagents only) Decide whether *you*, the agent currently executing this skill, are the top-level orchestrator (the agent talking directly to the user in this session) or a subagent — including a sub-subagent nested at any depth, launched via the `Agent` tool. - **You are a subagent (any depth):** you must NOT write the sidecar file unilaterally. Load `SendMessage` if not already available (`ToolSearch` query `select:SendMessage`), then call `SendMessage(to: "main", message: " — ")` and wait for `main`'s reply. Treat the reply as either a confirmation (proceed with the proposed name) or an adjusted name (use that name instead, still subject to Step 3's sanitize+cap). Only after this reply do you proceed to Step 7. The one caveat: `SendMessage` cannot bypass a permission prompt blocking you — the user's approve/deny is still required first if one is in the way. - **You are the top-level orchestrator:** no ping needed. Decide and proceed directly to Step 7, the same way `create-worktree` decides a feature name from a description without asking anyone else first. ## Step 7: Write the sidecar file atomically Never a direct `>` truncate-then-write — `status_line.sh` polls this file on a 1-second interval and must never observe a half-written or empty file mid-update. Every step is checked, and the temp file is removed on any failure — reporting a new name to the user after a write that did not land is worse than reporting the failure. ```bash NAME="" DEST="${CLAUDE_NOTIFY_TMP_DIR:-/tmp}/session_name_${CLAUDE_CODE_SESSION_ID}" tmp=$(mktemp "${CLAUDE_NOTIFY_TMP_DIR:-/tmp}/session_name_XXXXXX") || { echo "Error: could not create the temp file for the session name." >&2 exit 1 } if ! printf '%s' "$NAME" > "$tmp" || ! mv -f "$tmp" "$DEST"; then rm -f "$tmp" echo "Error: could not store the session name at $DEST." >&2 exit 1 fi ``` ## Step 8: Re-emit the tab title immediately This call site is a live skill invocation, not a hook — it has no JSON-output channel, so it must write the OSC 0 escape straight to the tty, the same way `create_worktree.sh` does, rather than waiting for the next Stop/waiting event to pick up the change. `_notify.sh` is already sourced from Step 2. `%s` is load-bearing: it prints `$NAME` as inert text, so nothing inside the name can be re-read as an escape. ```bash target_tty=$(_resolve_target_tty) printf '\033]0;%s\007' "$NAME" > "$target_tty" 2>/dev/null || true ``` ## Step 9: Report Tell the user the session name that is now stored (new or unchanged), and that they can re-run `/session-name` at any later point if the topic drifts — there is no limit on how many times it can run in a session.