Estimate your cost

Get a free Synkro cost estimate from your agents' existing session history.

synkro estimate shows your agent usage and estimates what checking that activity with Synkro would cost. It is free for signed-in accounts, including accounts without a saved card or balance. You can use session history from before you installed Synkro.

Get an estimate

Run this from a project with installed Rule packages:

synkro estimate

Or choose a project:

synkro estimate --path /work/payments

The command reads all available session history retained by Codex and Claude Code and calculates average daily usage, including inactive days. Codex history includes its sessions and archived_sessions directories, with both .jsonl and .jsonl.zst files. Copied records and resumed cumulative totals are not counted again. It shows one Synkro total in USD and a compact usage table. It does not run Rule checks or charge your account.

The first run reads your retained history. Later runs reuse local accounting for unchanged files and read new or changed files. Switching between day, week, month and year reuses the same history; prices and project Rules are evaluated again for each estimate. The cache contains usage accounting, not copied prompts or tool output. It lives under Synkro's state directory in estimate-cache; estimate_cache_dir can select another location. Removing it only makes the next run read the history again.

Choose how far to project that same average:

synkro estimate --day
synkro estimate --week
synkro estimate --month
synkro estimate --year

These flags project 1, 7, 30 and 365 days respectively; they do not filter history to the last day, week, month or year. The default is --month. Choose one flag.

If you have not set up project Rules yet, follow Quickstart and Rules. An estimate needs the selected project's installed packages. It does not download missing packages; run synkro lock to resolve them first.

Read the estimate

The report leads with your estimated Synkro spend for the chosen period. It also shows agent API-equivalent spend and Synkro's percentage when both estimates have complete matching coverage. The Average usage table shows tool calls and combined input/output tokens projected over that same period. Incomplete amounts or token counts are marked partial; partially priced agent spend is marked subtotal. The percentage is omitted when the two figures cannot be compared. Detailed coverage remains available with --json.

Only agents with recorded usage appear in the table. If you have history for just one, you get one row. If neither has usage, the command says so without inventing a zero-dollar estimate. Installing an agent without using it does not add an empty row.

Tables adapt to your terminal width. Set NO_COLOR=1 for uncolored output; --json includes the detailed coverage, model breakdowns and quote assumptions. Display precision comes from estimate_display in Settings: decimal_places for amounts, percentages and observed days, and usage_decimal_places for projected counts. Rounding does not change calculations or JSON values.

The summary adds the available agent rows into one Synkro total. Both costs use the same observed history and chosen projection. For example, a $6 Synkro estimate against $300 of model usage is 2%. Synkro is an additional cost, not a replacement for your coding agent or a claim that it saved $294.

The daily average is total recorded usage divided by elapsed days from the earliest retained timestamp through now. Every agent uses that same denominator, including quiet days and fractional days. Monthly averages are not averaged together: months with different lengths and activity levels contribute their actual totals. For example, 59,000 tokens over 59 days is 1,000 tokens per day, projected as 7,000 per week or 30,000 per month. The output shows the observed day count; JSON also includes the dates. Deleted history and sessions on other machines are not included. To use an archive, supply its uncompressed JSONL directory.

Model cost is API-equivalent, not your subscription bill. The calculation prices each recorded model separately and accounts for cached input, cache writes and supported long-context tiers. When cache-write duration is unreported, it uses short-lived cache rates. Discounts, speed or region premiums, subscriptions and extra tool fees are not included. Unknown models and incomplete pricing evidence stay null for those JSON samples; they are never silently priced as a different model. Known prices still contribute to a priced subtotal. Coverage shows how many usage records and tokens were priced in JSON, so that subtotal is not mistaken for the cost of your entire history. Missing model prices do not prevent a Synkro quote from valid tool-call records.

The bundled public rates have source URLs and verification dates in estimate_model_prices. You can override that list through Settings. JSON includes the rate source and date for each model. Rates are not fetched over the network when you run the command. Public rate references: model API pricing and Claude API pricing.

Actual Synkro charges depend on the actions checked, applicable Rules, retries and refunds. For recorded charges, use synkro account usage.

The selected project's installed Rules are used for every agent in the estimate. --path chooses that Rule package context; it does not filter session history to that repository. To compare Rule packages, rerun with a different project.

Your agent's token count describes its work, not the tokens used for Synkro checks. The estimate uses observed tool-call sizes and your Rule context, with its assumptions included in JSON. Input totals include reported cache usage, and output totals include reported reasoning usage. Those subsets are not extra tokens to add again.

Choose a history sample or session directory

synkro estimate --from 2026-10-01 --to 2026-10-21 --week
synkro estimate --session-root codex=/archive/codex/sessions
synkro estimate --session-root codex=/archive/codex/sessions --session-root claude_code=/archive/claude/projects

A date-only --to includes that whole day. Dates without an offset use your configured events_timezone (local time by default). See time formats. --from and --to optionally restrict the history used to calculate the average; they do not change the projection selected by --day, --week, --month or --year. Without these history filters, every flag uses all available history.

By default, Synkro looks in each agent's standard session directory. It also honors CODEX_HOME and CLAUDE_CONFIG_DIR. Use one --session-root HARNESS=PATH per agent to select another directory, such as an archive. Repeat the option for different agents. Names are codex and claude_code.

Available session data

In JSON, null means unavailable, not zero. Notes explain missing directories, unsupported formats or incomplete records. Valid, dated records still contribute to averages and projections when other records are incomplete. Those results are labeled partial observed evidence, with separate tool and token gaps in JSON. The terminal summary marks a partial estimate and omits an unsupported percentage. Synkro does not invent the missing activity or scale it up to fill those gaps. Without installed project Rules, usage can still be shown but the cost quote is unavailable.

Session files are read without changes, and symbolic links are skipped. If a scan reaches its file-count or total-byte limit, increase the corresponding setting or choose a smaller --session-root directory. Narrowing dates does not reduce how many files must be read. The byte budget includes decompressed data. Oversized records are checked without retaining their contents: known compaction and tool-output records do not create usage gaps, while missing tool or token evidence stays marked incomplete. Later records are still read. Known metadata-only files are not usage sessions. The limits are configurable with estimate_max_files, estimate_max_bytes, estimate_line_max_bytes and estimate_max_record_tokens; see Settings. estimate_buffer_max_bytes controls the bounded parsing buffer and must be at least estimate_line_max_bytes. It does not change which records count as usage. Cached accounting counts against the same file and decompressed-byte limits. estimate_scan_workers bounds parallel file readers (twelve by default). Each reader uses estimate_read_buffer_bytes for I/O and up to estimate_buffer_max_bytes for a record. These settings change scan throughput, not the history included or the resulting accounting.

Use JSON with your agent

synkro estimate --path /work/payments --json

JSON includes from, to, observed_days, period, projection_days, semantic_rules, policy_note, totals and a harnesses array. Each row includes usage, completeness notes, model-cost details, sample_quote, daily_average, estimated_synkro_usd, agent_api_equivalent_usd and synkro_percent_of_agent_cost. The same projection and daily-average fields appear in totals, along with harnesses_included. sample_quote.total_microusd uses millionths of a US dollar; projected cost fields are already in dollars. coverage on each row and the totals distinguishes complete, partial and unavailable metrics, and reports priced_records, observed_records, priced_tokens and observed_tokens. Totals add available amounts and retain partial coverage when a contributor is missing. An entirely unavailable metric remains null; missing session directories are not zero usage.

Ask your agent to compare usage across agents or explain the estimate using those assumptions. To see what Synkro has actually checked, use Activity and stats. To add funds or claim starter credit after skipping card setup, use Billing and usage.