Cost quote: Gemini paid tier for vanguard coding (for me's approval)

Prepared 2026-10-03, before the full-sample run, as I asked. Approved by me, 2026-10-03: up to $15 for the first month (the full run plus the first monthly runs), then up to $5 a month for three venues.

Raised by me, 2026-10-06: October's Gemini spending reached about $17.83 with the full run at 219 of 390 posts, because the billing account counts the trial work in the same month. I approved finishing the run ("approve finishing the Gemini coding, go with the recommendation"), about $4.40 more, taking October to about $22.20; do not go past about $22.50 without asking again. Details in the run record (pilot-run-r-singularity-2026-10.md).

Basis

Price: Google's published paid-tier rates for gemini-3.1-pro-preview: $2.00 per million input tokens and $12.00 per million output tokens, with the model's thinking counted as output (prompts under 200,000 tokens, which every post is). There is no free tier for this model and no monthly fee. The project is on Tier 1: billed after use, with a $250 spending cap and a limit of 250 requests per model per day.
Use per post, measured: with the rules appended to the codebook, which is the size of today's codebook with R2 and R3, the trial used about 3,050 input and 1,580 output tokens per post. That is $0.025 per post. Without the rules it was $0.022.
Posts per venue: the pilot screened about 29 top posts to reach 20 eligible per quarter, plus 20 random posts: about 49 posts per venue per quarter.
Venues: the three proposed enthusiast venues (r/singularity, r/accelerate, r/artificial). Skeptic venues, when they start, cost the same per venue.

Quote

item	posts	Gemini cost
Full-sample run: all 390 pilot posts under the final codebook	390	$9.80, one time (spread over 2 days by the daily limit)
Ongoing, one monthly run per venue, if each quarter's sample is coded in monthly parts	about 16 per venue	0.41pervenue; 1.23 a month for 3 venues
Ongoing, one monthly run per venue, if a full-size sample is drawn every month	about 49 per venue	1.23pervenue; 3.69 a month for 3 venues
A full recode of the pilot after any codebook change	390	$9.80 each time

Suggested approval: up to $15 for the first month (the full run plus the first monthly runs), then up to $5 a month for three venues. A budget alert in Google Cloud billing can enforce this.

Notes

Already committed today and tomorrow: the first trial's remaining 28 posts and the two split-rule trials (224 requests): about $6.30, billed to the same account.
Cheaper option: Google's batch mode is half price, but results arrive within hours rather than seconds. It would need a script change and a check that the pinned version is the same in batch mode.
The other two models, for the full picture: GPT-6 Astra costs about $0.054 per post. The full-sample run would be about $21, and the monthly runs $2.60 to $7.90 for three venues. After today's split-rule trials, about $10 of the $25 OpenAI credit will remain, so it will need topping up before the full run. Claude's coding runs inside the Claude Code session and has no separate per-post charge.
Prices are from Google's and third-party pages as of 2026-10-03; Google can change preview pricing.

Rendered from docs/vanguard/model-cost-quote-2026-10-03.md at version a7bd17a.