Auto-capture Claude Code sessions

Prerequisites

The hook script

Save the following as ~/.claude/hooks/hjarni-capture-note.sh and chmod +x it.

#!/usr/bin/env bash
set -euo pipefail

: "${HJARNI_URL:=https://hjarni.com}"
: "${HJARNI_TOKEN:?set HJARNI_TOKEN in your environment}"
: "${HJARNI_CLIENT:=claude-code}"
: "${HJARNI_CONTAINER_ID:=}"
: "${HJARNI_TAGS:=$HJARNI_CLIENT}"

payload=$(cat)

safe_jq_payload() {
  local filter="$1"
  printf '%s' "$payload" | jq -r "$filter" 2>/dev/null || true
}

safe_jq_file() {
  local filter="$1"
  [ -n "$transcript" ] && [ -f "$transcript" ] || return 0
  jq -rs "$filter" "$transcript" 2>/dev/null || true
}

normalize_for_hjarni() {
  local text="${1-}"
  printf '%s' "$text" | jq -Rrs '
    gsub("\\[(?<label>[^\\]]+)\\]\\(<?/(?<root>Users|tmp|var|private|home)/(?<path>[^)>]+):(?<line>\\d+)>?\\)";
         "`\(.label):\(.line)`")
    | gsub("\\[(?<label>[^\\]]+)\\]\\(<?/(?<root>Users|tmp|var|private|home)/(?<path>[^)>]+)>?\\)";
            "`\(.label)`")
  ' 2>/dev/null || printf '%s' "$text"
}

transcript=$(safe_jq_payload '.transcript_path // empty')
cwd=$(safe_jq_payload '.cwd // "unknown"')
session_id=$(safe_jq_payload '.session_id // "unknown"')
last_reply=$(safe_jq_payload '.last_assistant_message // empty')

cwd=${cwd:-unknown}
session_id=${session_id:-unknown}

[ -n "$last_reply" ] || exit 0

session_tag="session-$session_id"
timestamp=$(date -u +%Y-%m-%dT%H:%MZ)

# Prefer Codex's event_msg/user_message entries, which represent the actual user
# prompt and avoid injected context. Fall back to older transcript shapes only
# when those event entries are missing.
user_prompts='
  def event_prompts:
    [
      .[]
      | select(.type == "event_msg"
               and .payload.type == "user_message"
               and (.payload.message | type == "string"))
      | .payload.message
      | select(length > 0)
      | select(test("^<[a-z][a-z0-9_-]*>") | not)
    ];

  def legacy_prompts:
    [
      .[]
      | if .type == "response_item"
           and .payload.type == "message"
           and .payload.role == "user" then
          ([.payload.content[]? | select(.type == "input_text" and (.text | type == "string")) | .text] | join("\n"))
        elif .type == "user"
             and (.message.content | type == "string") then
          .message.content
        else
          empty
        end
      | select(length > 0)
      | select(test("^<[a-z][a-z0-9_-]*>") | not)
    ];

  if (event_prompts | length) > 0 then event_prompts else legacy_prompts end
'

last_prompt=""
last_prompt=$(safe_jq_file "$user_prompts | .[-1] // \"\"")
last_prompt=$(normalize_for_hjarni "$last_prompt")
last_reply=$(normalize_for_hjarni "$last_reply")

turn=$(printf '### %s\n\n**You:**\n\n%s\n\n**Claude:**\n\n%s' \
  "$timestamp" "${last_prompt:-(no prompt captured)}" "$last_reply")

existing=$(curl -fsS -G "$HJARNI_URL/api/v1/notes" \
  -H "Authorization: Bearer $HJARNI_TOKEN" \
  --data-urlencode "tag=$session_tag" \
  --data-urlencode "per_page=1") || exit 0

note_id=$(printf '%s' "$existing" | jq -r '.[0].id // empty' 2>/dev/null || true)

if [ -n "$note_id" ]; then
  current_body=$(printf '%s' "$existing" | jq -r '.[0].body // empty' 2>/dev/null || true)
  new_body=$(printf '%s\n\n---\n\n%s' "$current_body" "$turn")
  jq -n --arg body "$new_body" '{ note: { body: $body } }' \
    | curl -fsS -X PATCH "$HJARNI_URL/api/v1/notes/$note_id" \
        -H "Authorization: Bearer $HJARNI_TOKEN" \
        -H "Content-Type: application/json" \
        --data-binary @- >/dev/null || {
      echo "hjarni-capture-note: failed to append to note $note_id" >&2
      exit 0
    }
  exit 0
fi

first_prompt=""
first_prompt=$(safe_jq_file "($user_prompts | .[0] // \"\") | gsub(\"\\n\"; \" \")[:120]")
first_prompt=$(normalize_for_hjarni "$first_prompt")

validated_container_id=""
if [[ "$HJARNI_CONTAINER_ID" =~ ^[0-9]+$ ]]; then
  validated_container_id="$HJARNI_CONTAINER_ID"
elif [ -n "$HJARNI_CONTAINER_ID" ]; then
  echo "hjarni-capture-note: ignoring non-numeric HJARNI_CONTAINER_ID" >&2
fi

title=${first_prompt:-"Claude Code session $timestamp"}
body=$(printf '# %s\n\n**cwd:** `%s`\n**session:** `%s`\n\n---\n\n%s' \
  "$title" "$cwd" "$session_id" "$turn")

jq -n \
  --arg title "$title" \
  --arg body  "$body" \
  --arg src   "$HJARNI_CLIENT://$session_id" \
  --arg tags  "$HJARNI_TAGS,$session_tag" \
  --arg cid   "$validated_container_id" '
  {
    note: ({
      title: $title,
      body:  $body,
      source_url: $src,
      tag_list:   $tags
    } + (if $cid == "" then {} else { container_id: ($cid | tonumber) } end))
  }' \
  | curl -fsS -X POST "$HJARNI_URL/api/v1/notes" \
      -H "Authorization: Bearer $HJARNI_TOKEN" \
      -H "Content-Type: application/json" \
      --data-binary @- >/dev/null || {
    echo "hjarni-capture-note: failed to create note" >&2
    exit 0
  }

Wire it into settings.json

Add this to ~/.claude/settings.json (user-level) or .claude/settings.json (project-level):

{
  "env": {
    "HJARNI_TOKEN": "hj_xxxxxxxxxxxxxxxxxxxxxxxx",
    "HJARNI_TAGS": "claude-code"
  },
  "hooks": {
    "Stop": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "$HOME/.claude/hooks/hjarni-capture-note.sh"
          }
        ]
      }
    ]
  }
}

Prefer settings.local.json for the token so it stays out of version control. Or export HJARNI_TOKEN from your shell profile and drop it from env entirely.

Variations

Verify

export HJARNI_TOKEN=hj_xxx

echo '{"session_id":"test","transcript_path":"/tmp/empty.jsonl","cwd":"'"$PWD"'","last_assistant_message":"first turn"}' \
  | ~/.claude/hooks/hjarni-capture-note.sh

echo '{"session_id":"test","transcript_path":"/tmp/empty.jsonl","cwd":"'"$PWD"'","last_assistant_message":"second turn"}' \
  | ~/.claude/hooks/hjarni-capture-note.sh

curl -s -H "Authorization: Bearer $HJARNI_TOKEN" \
  "https://hjarni.com/api/v1/notes?tag=session-test" | jq '.[0] | {id, title, body}'

The first call creates a note tagged session-test. The second call finds it and appends. The body should contain both turns separated by a horizontal rule. Since the transcript path doesn't exist in this test, the prompt slot will read (no prompt captured). Real sessions will show the actual prompt.

Find a session later

Every session note is titled after your first prompt and the body is full-text indexed. Search however you prefer:

Related docs