thesisPrototype

Government data

Tokyo CPI annual rate, August 2026 preliminary

Statistics Bureau of Japan Consumer Price Index for Ku-area of Tokyo, all-items annual rate, August 2026 preliminary mid-month first print, non-seasonally adjusted; registered field 0001/all items and YoY computed from rounded index where the resolver provides index values.

Overdue · was due Sep 4, 2026

The resolver has no route for this target's reference. The target was registered with a generic source link rather than a resolver binding.

registration: series statjp.cpi.tokyo_all_items_yoy

NO_ROUTE_GENERIC_URL · resolver status as of Oct 7, 2026

Forecast

1.8%
1.3%–2.3%
80% prediction interval
gpt-5.5Run record ↗

Cumulative probability

Chance that the outcome is at or below each value.

0%25%50%75%100%0.55%1.8%3.05%Forecast value

Shaded band: 80% interval (1.3%–2.3%). Dashed line: point estimate (1.8%).

Derived from the point estimate and 80% interval; the agent did not report a full distribution.

Analysis

§Forecast for Tokyo all-items CPI annual rate, August 2026 preliminary

Framing: the target is Japan Statistics Bureau CPI for the Ku-area of Tokyo, all-items, August 2026 preliminary mid-month first print, non-seasonally adjusted, unit percent. Ledger discrepancy noted: the canonical target fixes resolutionDate 2026-09-04 and a 2020-base table-1-2 binding, while the official schedule fetched this run lists August 28, 2026 for the August Tokyo preliminary release and labels it the 2025-base CPI revision release.

▸ Reported tool use: official_calendar.fetchmodel report
curl -L -sS https://www.stat.go.jp/english/data/cpi/1582.html
↳ Fetched official CPI schedule: Last Update 23 January 2026; Ku-area of Tokyo preliminary August survey month date of release is August 28, 2026; the same row's remarks say Revision to 2025-Base Consumer Price Index. The ledger supplied resolutionDate is 2026-09-04, so the cell preserves 2026-09-04 and records the discrepancy.
▸ Reported tool use: official_page.fetchmodel report
curl -L -sS https://www.stat.go.jp/data/cpi/historic.html | iconv -f SHIFT_JIS -t UTF-8//IGNORE
↳ Fetched Statistics Bureau historical-data page: it states that 2020-base index series before December 2024 are converted to 2025=100 connected indices, and that 2025-base indices through the latest month are posted; Tokyo Ku-area monthly 2025-base link is lid=000001487885, with latest Tokyo month marked preliminary.
▸ Reported tool use: estat.csv.parsemodel report
curl -L -sS https://www.e-stat.go.jp/stat-search/file-download?statInfId=000040482965&fileKind=1; parse all-items column code 0001
↳ Fetched 2025-base Tokyo Ku-area monthly subgroup index CSV statInfId=000040482965 updated 2026-08-07. All-items rounded index and computed YoY: 2025-06 index 97.4 -> 2026-06 index 101.5 gives 1.6%; 2026-02 98.8/100.4 gives 1.6%; 2026-03 99.2/100.7 gives 1.5%; 2026-04 99.8/101.2 gives 1.4%; 2026-05 100.1/101.4 gives 1.3%.
▸ Reported tool use: estat.workbook.parsemodel report
curl -L -sS https://www.e-stat.go.jp/stat-search/file-download?statInfId=000040475902&fileKind=0; parse e-Stat 2020-base table 1-2 workbook
↳ Fetched latest old-method Tokyo table 1-2 workbook statInfId=000040475902 published 2026-07-31. All-items code 0001: 2026-06 index 112.7 and YoY 1.7%; 2026-07 preliminary index 113.2 and YoY 2.0%. This is a current directional signal but not the revised 2025-base history.
▸ Reported tool use: catalog.slug_checkmodel report
curl -L -sS https://app.thesisinstitute.org/specs.json
↳ Checked live specs endpoint for slug japan-tokyo-cpi-annual-rate-august-2026-prelim: contains_target_slug=False; response body returned a 404 shell, so no duplicate slug was found from the fetched endpoint.

Base rate/reference class: the reference class is recent revised 2025-base Tokyo Ku-area all-items annual-rate prints computed from the official rounded index. The last 12 revised YoY rates are 3.0, 2.8, 2.5, 2.8, 2.6, 1.9, 1.6, 1.6, 1.5, 1.4, 1.3, and 1.6 percent for 2025-07 through 2026-06. Last-print persistence is 1.6%; the mean recent successive YoY change is -0.127 percentage point, so the simple mean-change candidate is 1.5%.

Model candidates under thesis_model_candidate_v1: persistence_yoy has point 1.6, p10 1.3, p50 1.6, p90 1.9, 80% interval [1.3, 1.9], 90% interval [1.2, 2.0], train cutoff 2026-06, interval method successive-yoy-change residual sigma from revised 2025-base history, calibration_n 11. mean_recent_yoy_change has point 1.5, p10 1.1, p50 1.5, p90 1.8, 80% interval [1.1, 1.8], 90% interval [1.0, 1.9], same interval method and calibration_n 11. I select persistence as the prior and adjust only modestly because the July signal is old-base.

Prior/update/interval: persistence prior is revised 2025-base June 2026 all-items YoY at 1.6. Historical sample is the last 12 revised 2025-base YoY values through 2026-06; successive changes are -0.2, -0.3, +0.3, -0.2, -0.7, -0.3, +0.0, -0.1, -0.1, -0.1, +0.3 percentage point, so sigma = 0.267. Adjustment components: +0.15 pp for the fetched old-base July preliminary rise to 2.0%, +0.05 pp for August base-revision transition/current-food-energy uncertainty, giving 1.6 + 0.15 + 0.05 = 1.8. The raw 80% half-width is roughly 1.28*sigma = 1.28*0.267 = 0.342 pp; I widen to 0.5 pp, 1.46x raw, because the revised-methodology history lacks a July 2026 print and August is the scheduled base-revision release. Final implied bounds: 1.8 - 0.5 = 1.3 and 1.8 + 0.5 = 2.3.

Counter-considerations: upside risk would be fresh-food or energy price pressure carrying through the 2025-base August print, or a stronger translation of the 2020-base July 2.0% signal, which would land above the interval if the first print exceeded 2.3%. Downside risk would be a revised-base July/August cooling hidden by the old-base July signal or lower rents/food services inflation, which would land below the interval if the print came in under 1.3%. An outside the interval result would mainly indicate that the base revision or omitted revised July print moved more than the recent 2025-base change distribution.

Review disposition: accepted the resolver critique by removing the 2025-base fallback from the resolution rule and keeping the formal resolver anchored to the registered sourceBinding, field 0001, first_print policy, dataPointId, and ledger resolutionDate. The 2025-base schedule/revision issue remains only as a public discrepancy and uncertainty note in the reasoning.

Key drivers

  • 2025-base revised history ends at 1.6% in June 2026
  • Old-base July preliminary signal rose to 2.0%
  • Recent revised YoY changes average mildly negative
  • August 2026 release is scheduled as a base-revision month
  • Interval widened for missing revised-method July print

Tool evidence

This run has no captured tool responses. “Reported tool use” in the analysis is the model’s account, not an archived tool response.

Sources and resolution

Official source
Statistics Bureau of Japan, Consumer Price Index Ku-area of Tokyo preliminary
Resolution date
September 4, 2026· outcome not recorded
Resolution rule
Resolve to the first official Statistics Bureau of Japan/e-Stat Tokyo Ku-area preliminary CPI release for August 2026 using the registered sourceBinding: 2020-base CPI Tokyo ku-area mid-month preliminary; machine-readable vintage is the release's e-Stat table 1-2 workbook, all items, series code/field 0001, annual rate computed YoY from rounded all-items index, first_print policy. Later revisions are ignored. The supplied ledger contract fixes resolutionDate at 2026-09-04.
Run details

The analysis is the model’s written report. Tool-use descriptions in that report are model claims; the activity artifacts contain the execution record.

thesis.analyst · gpt-5.5 · full · v2.5.9

pre-submit review · completed

Draft is publishable after tightening the resolver language so the JSON does not broaden the ledger-bound source contract.

  • warning resolver: The resolutionRule adds a 2025-base fallback that can read like a changed resolver rather than a disclosed ledger discrepancy.
  • info optional_suggestion: The prior/update/interval step is strong; consider shortening the resolver discrepancy sentence to reduce ambiguity.
  • info optional_suggestion: The catalog.slug_check against a 404 shell is not material to the forecast and can be omitted from reasoning if space is constrained.

disposition accepted: Review disposition: accepted the resolver critique by removing the 2025-base fallback from the resolution rule and keeping the formal resolver anchored to the registered sourceBinding, field 0001, first_print policy, dataPointId, and ledger resolutionDate. The 2025-base schedule/revision issue remains only as a public discrepancy and uncertainty note in the reasoning.

disposition not applicable: Review disposition: accepted the resolver critique by removing the 2025-base fallback from the resolution rule and keeping the formal resolver anchored to the registered sourceBinding, field 0001, first_print policy, dataPointId, and ledger resolutionDate. The 2025-base schedule/revision issue remains only as a public discrepancy and uncertainty note in the reasoning.

disposition not applicable: Review disposition: accepted the resolver critique by removing the 2025-base fallback from the resolution rule and keeping the formal resolver anchored to the registered sourceBinding, field 0001, first_print policy, dataPointId, and ledger resolutionDate. The 2025-base schedule/revision issue remains only as a public discrepancy and uncertainty note in the reasoning.

Activity artifacts

Complete original trace

§Forecast for Tokyo all-items CPI annual rate, August 2026 preliminary

Framing: the target is Japan Statistics Bureau CPI for the Ku-area of Tokyo, all-items, August 2026 preliminary mid-month first print, non-seasonally adjusted, unit percent. Ledger discrepancy noted: the canonical target fixes resolutionDate 2026-09-04 and a 2020-base table-1-2 binding, while the official schedule fetched this run lists August 28, 2026 for the August Tokyo preliminary release and labels it the 2025-base CPI revision release.

▸ Reported tool use: official_calendar.fetchmodel report
curl -L -sS https://www.stat.go.jp/english/data/cpi/1582.html
↳ Fetched official CPI schedule: Last Update 23 January 2026; Ku-area of Tokyo preliminary August survey month date of release is August 28, 2026; the same row's remarks say Revision to 2025-Base Consumer Price Index. The ledger supplied resolutionDate is 2026-09-04, so the cell preserves 2026-09-04 and records the discrepancy.
▸ Reported tool use: official_page.fetchmodel report
curl -L -sS https://www.stat.go.jp/data/cpi/historic.html | iconv -f SHIFT_JIS -t UTF-8//IGNORE
↳ Fetched Statistics Bureau historical-data page: it states that 2020-base index series before December 2024 are converted to 2025=100 connected indices, and that 2025-base indices through the latest month are posted; Tokyo Ku-area monthly 2025-base link is lid=000001487885, with latest Tokyo month marked preliminary.
▸ Reported tool use: estat.csv.parsemodel report
curl -L -sS https://www.e-stat.go.jp/stat-search/file-download?statInfId=000040482965&fileKind=1; parse all-items column code 0001
↳ Fetched 2025-base Tokyo Ku-area monthly subgroup index CSV statInfId=000040482965 updated 2026-08-07. All-items rounded index and computed YoY: 2025-06 index 97.4 -> 2026-06 index 101.5 gives 1.6%; 2026-02 98.8/100.4 gives 1.6%; 2026-03 99.2/100.7 gives 1.5%; 2026-04 99.8/101.2 gives 1.4%; 2026-05 100.1/101.4 gives 1.3%.
▸ Reported tool use: estat.workbook.parsemodel report
curl -L -sS https://www.e-stat.go.jp/stat-search/file-download?statInfId=000040475902&fileKind=0; parse e-Stat 2020-base table 1-2 workbook
↳ Fetched latest old-method Tokyo table 1-2 workbook statInfId=000040475902 published 2026-07-31. All-items code 0001: 2026-06 index 112.7 and YoY 1.7%; 2026-07 preliminary index 113.2 and YoY 2.0%. This is a current directional signal but not the revised 2025-base history.
▸ Reported tool use: catalog.slug_checkmodel report
curl -L -sS https://app.thesisinstitute.org/specs.json
↳ Checked live specs endpoint for slug japan-tokyo-cpi-annual-rate-august-2026-prelim: contains_target_slug=False; response body returned a 404 shell, so no duplicate slug was found from the fetched endpoint.

Base rate/reference class: the reference class is recent revised 2025-base Tokyo Ku-area all-items annual-rate prints computed from the official rounded index. The last 12 revised YoY rates are 3.0, 2.8, 2.5, 2.8, 2.6, 1.9, 1.6, 1.6, 1.5, 1.4, 1.3, and 1.6 percent for 2025-07 through 2026-06. Last-print persistence is 1.6%; the mean recent successive YoY change is -0.127 percentage point, so the simple mean-change candidate is 1.5%.

Model candidates under thesis_model_candidate_v1: persistence_yoy has point 1.6, p10 1.3, p50 1.6, p90 1.9, 80% interval [1.3, 1.9], 90% interval [1.2, 2.0], train cutoff 2026-06, interval method successive-yoy-change residual sigma from revised 2025-base history, calibration_n 11. mean_recent_yoy_change has point 1.5, p10 1.1, p50 1.5, p90 1.8, 80% interval [1.1, 1.8], 90% interval [1.0, 1.9], same interval method and calibration_n 11. I select persistence as the prior and adjust only modestly because the July signal is old-base.

Prior/update/interval: persistence prior is revised 2025-base June 2026 all-items YoY at 1.6. Historical sample is the last 12 revised 2025-base YoY values through 2026-06; successive changes are -0.2, -0.3, +0.3, -0.2, -0.7, -0.3, +0.0, -0.1, -0.1, -0.1, +0.3 percentage point, so sigma = 0.267. Adjustment components: +0.15 pp for the fetched old-base July preliminary rise to 2.0%, +0.05 pp for August base-revision transition/current-food-energy uncertainty, giving 1.6 + 0.15 + 0.05 = 1.8. The raw 80% half-width is roughly 1.28*sigma = 1.28*0.267 = 0.342 pp; I widen to 0.5 pp, 1.46x raw, because the revised-methodology history lacks a July 2026 print and August is the scheduled base-revision release. Final implied bounds: 1.8 - 0.5 = 1.3 and 1.8 + 0.5 = 2.3.

Counter-considerations: upside risk would be fresh-food or energy price pressure carrying through the 2025-base August print, or a stronger translation of the 2020-base July 2.0% signal, which would land above the interval if the first print exceeded 2.3%. Downside risk would be a revised-base July/August cooling hidden by the old-base July signal or lower rents/food services inflation, which would land below the interval if the print came in under 1.3%. An outside the interval result would mainly indicate that the base revision or omitted revised July print moved more than the recent 2025-base change distribution.

Review disposition: accepted the resolver critique by removing the 2025-base fallback from the resolution rule and keeping the formal resolver anchored to the registered sourceBinding, field 0001, first_print policy, dataPointId, and ledger resolutionDate. The 2025-base schedule/revision issue remains only as a public discrepancy and uncertainty note in the reasoning.

calibrated forecast · 80% CI
1.8%[1.3% · 2.3%]
Target metadata

Data point: statjp.cpi.tokyo_all_items_annual_rate.august_2026.preliminary

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