Available data

Claude Code sends the following JSON fields to your script via stdin:

Field	Description
model.id, model.display_name	Current model identifier and display name
cwd, workspace.current_dir	Current working directory. Both fields contain the same value; workspace.current_dir is preferred for consistency with workspace.project_dir.
workspace.project_dir	Directory where Claude Code was launched, which may differ from cwd if the working directory changes during a session
workspace.added_dirs	Additional directories added via /add-dir or --add-dir. Empty array if none have been added
workspace.git_worktree	Git worktree name when the current directory is inside a linked worktree created with git worktree add. Absent in the main working tree. Populated for any git worktree, unlike worktree.*, which is present only while the session is in a worktree session
workspace.repo.host, workspace.repo.owner, workspace.repo.name	Repository identity parsed from the origin remote, for example, "github.com", "anthropics", "claude-code". Absent outside a git repository or when no origin remote is configured. For a gitlab.com project nested in subgroups, owner is the full namespace path with slashes, such as "group/subgroup". Before v2.1.260, workspace.repo was absent for these projects
cost.total_cost_usd	Estimated session cost in USD, computed client-side at list price unless a modelPricing table is in effect. May differ from your actual bill. Resets to $0 when /clear starts a new session. Before v2.1.211, the total carried over after /clear
cost.total_duration_ms	Total wall-clock time since the session started, in milliseconds
cost.total_api_duration_ms	Total time spent waiting for API responses in milliseconds
cost.total_lines_added, cost.total_lines_removed	Lines of code changed
context_window.total_input_tokens, context_window.total_output_tokens	Token counts currently in the context window, from the most recent API response. Input includes cache reads and writes
context_window.context_window_size	Maximum context window size in tokens. 200000 by default, or 1000000 for models with extended context.
context_window.used_percentage	Pre-calculated percentage of context window used
context_window.remaining_percentage	Pre-calculated percentage of context window remaining
context_window.current_usage	Token counts from the last API call, described in context window fields
exceeds_200k_tokens	Whether the total token count (input, cache, and output tokens combined) from the most recent API response exceeds 200k. This is a fixed threshold regardless of actual context window size.
fast_mode	Whether fast mode is enabled for the session
effort.level	Current reasoning effort (low, medium, high, xhigh, or max). Reflects the live session value, including mid-session /effort changes. Ultracode is not a distinct level and reports as xhigh. Absent when the current model does not support the effort parameter
thinking.enabled	Whether extended thinking is enabled for the session
rate_limits.five_hour.used_percentage, rate_limits.seven_day.used_percentage	Percentage of the 5-hour or 7-day rate limit consumed, from 0 to 100
rate_limits.five_hour.resets_at, rate_limits.seven_day.resets_at	Unix epoch seconds when the 5-hour or 7-day rate limit window resets
rate_limits.spend_limit.used_percentage, rate_limits.spend_limit.resets_at	Behind a Claude apps gateway, the percentage used of the spend limit that applies to you, and the Unix epoch seconds when its period resets. The percentage runs from 0 to 100, or above 100 once you exceed the limit. Requires Claude Code v2.1.251 or later
prompt_cache	The session's prompt cache statistics for the main conversation: hit ratio, misses, and whether the cache is warm. See prompt cache fields for every field. Absent until the main conversation's first API response. Requires Claude Code v2.1.251 or later
session_id	Unique session identifier
session_name	Session name. Uses the custom name set with the --name flag or /rename when one exists, otherwise the AI-generated session title. The default display name, such as my-app-3f, doesn't populate this field. Absent when the session has neither a custom name nor an AI-generated title
prompt_id	UUID identifying the user prompt currently being processed. Matches the prompt.id attribute on OpenTelemetry events. Absent until the first user input. Requires Claude Code v2.1.196 or later
transcript_path	Path to conversation transcript file
version	Claude Code version
output_style.name	Name of the current output style
vim.mode	Current vim mode (NORMAL, INSERT, VISUAL, or VISUAL LINE) when vim mode is enabled
agent.name	Agent name when running with the --agent flag or agent settings configured
pr.number, pr.url	Open pull request for the current branch. Mirrors the PR badge in the footer. In a repository with a GitLab remote, Claude Code fills these fields from the branch's open merge request instead, so pr.number is the merge request number. Merge request data requires Claude Code v2.1.234 or later. Absent when not in a git repository, until a pull request or merge request is found, or once it merges or closes
pr.review_state	Review status of the open PR: approved, pending, changes_requested, or draft. May be independently absent even when pr is present
pr.kind	mr when pr describes a GitLab merge request. Absent for GitHub pull requests, so scripts written before this field keep working. For a merge request, Claude Code sets review_state to approved when GitLab reports it mergeable, pending for any other open state, and draft for a draft. Requires Claude Code v2.1.234 or later
worktree.name	Name of the active worktree. Present only while the session is in a worktree session
worktree.path	Absolute path to the worktree directory
worktree.branch	Git branch name for the worktree (for example, "worktree-my-feature"). Absent for hook-based worktrees
worktree.original_cwd	The directory Claude was in before entering the worktree
worktree.original_branch	Git branch checked out before entering the worktree. Absent for hook-based worktrees

Your status line command receives this JSON structure via stdin:

{
  "cwd": "/current/working/directory",
  "session_id": "abc123...",
  "session_name": "my-session",
  "prompt_id": "550e8400-e29b-41d4-a716-446655440000",
  "transcript_path": "/path/to/transcript.jsonl",
  "model": {
    "id": "claude-opus-5",
    "display_name": "Opus"
  },
  "workspace": {
    "current_dir": "/current/working/directory",
    "project_dir": "/original/project/directory",
    "added_dirs": [],
    "git_worktree": "feature-xyz",
    "repo": {
      "host": "github.com",
      "owner": "anthropics",
      "name": "claude-code"
    }
  },
  "version": "2.1.90",
  "output_style": {
    "name": "default"
  },
  "cost": {
    "total_cost_usd": 0.01234,
    "total_duration_ms": 45000,
    "total_api_duration_ms": 2300,
    "total_lines_added": 156,
    "total_lines_removed": 23
  },
  "context_window": {
    "total_input_tokens": 15500,
    "total_output_tokens": 1200,
    "context_window_size": 200000,
    "used_percentage": 8,
    "remaining_percentage": 92,
    "current_usage": {
      "input_tokens": 8500,
      "output_tokens": 1200,
      "cache_creation_input_tokens": 5000,
      "cache_read_input_tokens": 2000
    }
  },
  "exceeds_200k_tokens": false,
  "prompt_cache": {
    "warm": true,
    "caching_observed": true,
    "ttl": "1h",
    "expires_at": 1738429200,
    "requests": 14,
    "misses": 2,
    "expected_rebuilds": 1,
    "hit_ratio": 0.91,
    "cache_write_tokens": 352000,
    "miss_recache_tokens": 310200,
    "last_miss_at": 1738425230,
    "last_miss_cause": {
      "causes": ["tools_changed"],
      "tools_added": 2,
      "tools_removed": 0
    },
    "miss_causes": {
      "tools_changed": 2
    },
    "recache_tokens_if_cold": 45000
  },
  "fast_mode": false,
  "effort": {
    "level": "high"
  },
  "thinking": {
    "enabled": true
  },
  "rate_limits": {
    "five_hour": {
      "used_percentage": 23.5,
      "resets_at": 1738425600
    },
    "seven_day": {
      "used_percentage": 41.2,
      "resets_at": 1738857600
    },
    "spend_limit": {
      "used_percentage": 62.8,
      "resets_at": 1740787200
    }
  },
  "vim": {
    "mode": "NORMAL"
  },
  "agent": {
    "name": "security-reviewer"
  },
  "pr": {
    "number": 1234,
    "url": "https://github.com/anthropics/claude-code/pull/1234",
    "review_state": "pending"
  },
  "worktree": {
    "name": "my-feature",
    "path": "/path/to/.claude/worktrees/my-feature",
    "branch": "worktree-my-feature",
    "original_cwd": "/path/to/project",
    "original_branch": "main"
  }
}

Fields that may be absent (not present in JSON):

• session_name: appears when a custom name has been set with --name or /rename, or once an AI-generated session title exists. The default display name, such as my-app-3f, doesn't populate it
• prompt_id: appears only after the first user input
• workspace.git_worktree: appears only when the current directory is inside a linked git worktree
• workspace.repo: appears only inside a git repository with an origin remote configured
• effort: appears only when the current model supports the reasoning effort parameter
• vim: appears only when vim mode is enabled
• agent: appears only when running with the --agent flag or agent settings configured
• pr: appears only while an open PR or GitLab merge request is found for the current branch, and is removed once it merges or closes. pr.review_state and pr.kind may be independently absent
• worktree: appears only while the session is in a worktree session. When present, branch and original_branch may also be absent for hook-based worktrees
• rate_limits: appears only for Claude.ai Pro and Max subscribers, or behind a Claude apps gateway that sets a spend limit for you, and only after the first API response in the session. Each window (five_hour, seven_day, spend_limit) may be independently absent, and Claude Code drops a window once its resets_at time passes. Use jq -r '.rate_limits.five_hour.used_percentage // empty' to handle absence gracefully.
• prompt_cache: appears after the main conversation's first API response. See prompt cache fields

Fields that may be null:

• context_window.current_usage: null before the first API call in a session, and again after /compact until the next API call repopulates it
• context_window.used_percentage, context_window.remaining_percentage: may be null early in the session

Handle missing fields with conditional access and null values with fallback defaults in your scripts.

Context window fields

The context_window object describes the live context window from the most recent API response.

• Combined totals (total_input_tokens, total_output_tokens): tokens currently in the context window. total_input_tokens is the sum of input_tokens, cache_creation_input_tokens, and cache_read_input_tokens; total_output_tokens is the output tokens from the most recent response. Both are 0 before the first API response.
• Per-component usage (current_usage): the same token counts broken out by category. Use this when you need cache hits separate from fresh input.

The current_usage object contains:

• input_tokens: input tokens in current context
• output_tokens: output tokens generated
• cache_creation_input_tokens: tokens written to cache
• cache_read_input_tokens: tokens read from cache

For what the cache fields mean and how they're billed, see check cache performance.

The used_percentage field is calculated from input tokens only: input_tokens + cache_creation_input_tokens + cache_read_input_tokens. It does not include output_tokens.

If you calculate context percentage manually from current_usage, use the same input-only formula to match used_percentage.

The current_usage object is null before the first API call in a session, and again immediately after /compact until the next API call repopulates it.

Prompt cache fields

The prompt_cache object summarizes how the session's main conversation is using the prompt cache. Claude Code computes it from the cache token counts in the API's responses, so it works on every provider.

The object appears after the main conversation's first API response. Claude Code doesn't count subagent requests in these statistics. Requires Claude Code v2.1.251 or later.

The table lists each field with its meaning. Timestamps are Unix epoch seconds, the same unit as rate_limits.*.resets_at. A short status line usually shows one or two of these; warm and hit_ratio summarize the cache state most directly.

Field	Description
warm	Whether the cached prefix is still within its TTL. false when the last response reported no cache tokens, even while caching_observed is true
caching_observed	Whether any response this session reported cache tokens. false means prompt caching is off, or your provider or gateway doesn't report it
ttl	Cache lifetime of the current cached prefix: "5m" or "1h"
expires_at	When the cached prefix leaves its TTL and goes cold, in epoch seconds. null when the last response reported no cache tokens
requests	API requests recorded for the main conversation this session
misses	Requests that re-processed content the cache already held: more than 5% and at least 2,000 tokens of what the request could have read from cache, with no compaction or tool-result clearing to explain the shortfall in cache reads
expected_rebuilds	Cache rebuilds that followed a compaction or a clearing of old tool results
hit_ratio	Cache read tokens as a fraction of all input tokens this session, from 0 to 1. The denominator counts cache reads, cache writes, and uncached input. null while those counts are all zero
cache_write_tokens	All tokens written to the cache this session, the first request's initial write included
miss_recache_tokens	Tokens written to the cache by the requests counted as misses
last_miss_at	When the last miss happened, in epoch seconds. null while the session has no misses
last_miss_cause	What Claude Code identified as the likely cause of the last miss, described under Last miss cause. Requires Claude Code v2.1.260 or later
miss_causes	How many of this session's diagnosed misses had each cause, keyed by the same cause names as last_miss_cause. Requires Claude Code v2.1.260 or later
recache_tokens_if_cold	Tokens the next request re-caches if the cache has gone cold by then. null right after a compaction or a clearing of old tool results, until the next request records the rewritten conversation's size

Claude Code shows the same statistics in the terminal, on the /usage command's Prompt cache (main) line.

Last miss cause

The last_miss_cause object reports what Claude Code identified as the likely cause of the most recent miss. Its causes array holds one or more cause names, such as tools_changed, system_prompt_changed, ttl_expired_5m, or likely_server_side. The object is null until the session's first miss, and again whenever Claude Code couldn't identify a cause for the most recent miss. Requires Claude Code v2.1.260 or later.

Two causes add counts to the object:

• tools_added and tools_removed: with tools_changed, how many tools were added to or removed from the request
• system_char_delta: with system_prompt_changed, the change in the system prompt's length, in characters