November changelog: Runtimes & OIDC cloud credentials, plus imports with Claude Code & opencode
How Claude Fable 5.1 did on iac-bench 2026-10: an overall composite of 86.9, scores per fixture, strengths, weaknesses and the patterns in its OpenTofu modules.
All ten models side by side, with a sortable leaderboard, picks by use case and the cost of each: LLM rankings.
| Developer | Anthropic |
| API identifier | claude-fable-5-1 |
| Access | Anthropic API |
| Weights | Closed |
| List price (USD / M tokens, in / out) | 10.00 / 50.00 (OpenRouter, 2026-10-23) |
| Evaluated | 2026-10-22 (generation) · 2026-10-23 (judge) |
| Attempts | 9 (3 fixtures × 3 samples) |
| Overall composite | 86.9 (95% CI 83.7–90.2) |
| Rank | 2 of 10 (95% rank interval 1–5) |
| Mechanical only / judge only | 85.0 (rank 2) / 91.2 (rank 5) |
| Failed gates · insecure attempts | 0/9 · 0/9 |
| Estimated cost, all 9 attempts | $13.97 |
Claude Fable 5.1 places second, close behind Claude Opus 5.5. All 9 modules planned, and none had a security finding. Together with Claude Opus 5.5, it shows the deepest service expertise in the field on Cloud SQL and App Service (median 8/9 and 5/5 expertise items).
Its cost is the main counterweight: it was the most expensive model on every fixture, at nearly four times the per-attempt cost of Claude Opus 5.5. Its interfaces are also consistently larger than the benchmark's budget for each audience.
| Fixture | Composite median (range) | Rubric median | Expertise | Judge median | ✗ gate | ⚠ security | Median inputs | Median output tokens | Median time | Median cost |
|---|---|---|---|---|---|---|---|---|---|---|
| G001 · S3 | 85.6 (82.6–90.2) | 0.826 | 6/7 | 92.1 | 0/3 | 0/3 | 12 | 12,112 | 302 s | $0.935 |
| G002 · Cloud SQL | 85.6 (79.0–90.0) | 0.832 | 8/9 | 94.7 | 0/3 | 0/3 | 30 | 14,402 | 196 s | $1.229 |
| G003 · App Service | 89.5 (88.5–94.9) | 0.911 | 5/5 | 86.8 | 0/3 | 0/3 | 28 | 27,308 | 566 s | $2.157 |
Rubric items not at full credit, counted over attempts that planned: G001: A5 3/3, B1 3/3, H12 2/3, H13 3/3, H15 1/3; G002: A8 3/3, B1 3/3, H4 3/3, H5 3/3, H10 1/3, H11 3/3; G003: A7 3/3. Definitions are in Scoring criteria.
environment input sets the
network (apps-<env>), the HA type and backup retention. terraform_data guard on App Service that holds five capacity rules.A5, 11–13 inputs against 8. A8, 26–37 inputs against 25. One attempt scored zero. A7, 27–29 inputs against 20. intelligent_tiering_after_days.>=, or >= 5.30, < 7.0, in
6 of 9 attempts (B1). H11 lost in 3/3). One
attempt adds a deletion_policy input, but its default is DELETE. One attempt also
writes a break-glass password into state (H10). H13, 3/3). observability.tf, scaling.tf,
slot.tf), but still lets main.tf grow past 200 lines in 4/9 attempts.for_each for multiplicity and count only as a switch.
G002/claude-fable-5-1-e1/main.tf lines 11–21
enforced_database_flags = {
"cloudsql.iam_authentication" = "on"
"log_connections" = "on"
"log_disconnections" = "on"
"log_checkpoints" = "on"
"log_lock_waits" = "on"
"log_temp_files" = "0"
}
database_flags = merge(var.database_flags, local.enforced_database_flags)
The same pattern as the leader, with a broader enforced audit set: connections, disconnections, checkpoints, lock waits and temporary files are always logged.
How Claude Haiku 5.5 did on iac-bench 2026-10: an overall composite of 68.0, scores per fixture, strengths, weaknesses and the patterns in its OpenTofu modules.
How Claude Opus 5.5 did on iac-bench 2026-10: an overall composite of 88.9, scores per fixture, strengths, weaknesses and the patterns in its OpenTofu modules.
How Claude Sonnet 5.5 did on iac-bench 2026-10: an overall composite of 86.1, scores per fixture, strengths, weaknesses and the patterns in its OpenTofu modules.