Handoff Cost 2

Handoff Cost (Part 2)

This page keeps the older measurement, on the earlier release 1.0.0. The measurement of 0.2.0 is on Handoff Cost. This page compares the cost of one handoff with the cost of one /compact on the same session. On this session, the handoff cost $0.0630 and the compaction cost $0.2288. The figures are from the earlier release (1.0.0), not from the handoff slice of 0.2.0. That slice works another way: it runs at each compaction (Handoff).

Setup

Item	Value
Date	2026-10-12, 17:32 to 17:34 UTC
Claude Code	2.1.296
Model	claude-sonnet-5-5, context window 1,000,000 tokens
Checkout	Commit 627d1d22 of the earlier release
Session	just sandbox after just sandbox-clean, in a project with four slices of that release
Runs	4: one base, one handoff fork, one compaction fork, one follow-up

All runs used just sandbox --model claude-sonnet-5-5 --output-format stream-json --verbose. The base run read 31 files with Read. Its last call had a context of 81,316 tokens. Both forks started from that context with --fork-session. The handoff fork wrote a handoff file (1,585 bytes) and ran /clear, and the new session read it and answered. The compaction fork ran /compact, then got the follow-up Continue the work.

Sources

Source	Content
S	usage and total_cost_usd of the result events in stream-json
T	cost-state and compact_boundary entries and assistant usage in the transcripts. A fork starts with the cost-state of its base, so a step is the difference of two cost-state values
U	The usage report of that release, used as a check only

Handoff

Measure	Handoff step	Resume step	Total	Source
Input tokens (not cached)	6	4	10	S
Cache read tokens	164,242	25,946	190,188	S
Cache write tokens	2,576	5,874	8,450	S
Output tokens	869	147	1,016	S
Model calls	2	2	4	T
Cost (API list price)	$0.0354	$0.0276	$0.0630	S
Context, last call of the step	82,927	18,487	18,487	T
Time	6.7 s	2.4 s	9.1 s	S

Compaction

Measure	/compact step	Follow-up step	Total	Source
Input tokens (not cached)	59,526	2	59,528	T
Cache read tokens	20,245	12,613	32,858	T
Cache write tokens	3,542	15,803	19,345	T
Output tokens	3,049	391	3,440	T
Model calls	not shown	1	not shown	T
Cost (API list price)	$0.1604	$0.0684	$0.2288	S
Context, first call of the follow-up	7,835 (postTokens)	28,418	28,418	T
Time	18.8 s	4.4 s	23.2 s	T and S

Read the context rows as two different points, not as one measure.

Result

• The summary call of the compaction read 59,526 uncached tokens and wrote 3,049 output tokens.
• The handoff made no such call.
• The handoff took 9.1 s, and the compaction with its follow-up took 23.2 s.
• The sums of the usage report (source U) do not match the tables. A fork copies the history of its base, and the report does not show the /compact call.

Limits

• One session of about 81,000 tokens, one model, and one run of each step. The numbers have no spread.
• The /compact call is not in the transcript as a message, so its call count is unknown.
• The cost is the API list price, not a subscription limit. Sources S and T come from the same client.
• The quality of the continued work is not measured.
• Cache expiry is not measured. The steps ran within two minutes, with a one-hour cache.

See Also

• Handoff Cost
• Usage Evidence
• Handoff
• Evidence