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Curtail

ReGrade®

Behavioral evidence for release decisions

Field-level analysis that catches regressions in API behavior by comparing real traffic across software versions.

Plan an evaluationTry For Free

Evaluate one service before expanding

Choose a baseline and candidate build, then record and replay representative requests in an isolated test environment. Have your team review the differences before deciding which findings should block a merge or release. Replayed traffic cannot cover paths you did not exercise or identify every vulnerability.

Measure repair results and review effort alongside LLM API spend, subscription fees and replay infrastructure. Agree on success criteria before requiring the workflow across your organization.

Hosted or in your infrastructure

Use the hosted ReGrade service, or discuss deployment in your own data center or private cloud. The recording proxy captures request headers and bodies as well as responses; captured data is uploaded to the storage used by your ReGrade deployment. Review sensitive-data handling before recording production traffic.

Access checks use organization and team permissions. Authorized users can request recording deletion. Discuss retention, redaction requirements and deployment controls with us before an evaluation; recording and agent integration require setup.

See the agent connection and recording setup

See it in action

See all demos →

How Curtail's ReGrade can help you

The same agent, the same bugs, a third of the time

We gave Claude Code the same codebase, the same two known bugs, and the same AI model. One session had ReGrade's structured differences to work from. The other had raw traffic replay. Here is what happened.

Ghost CMS v2.2.2 → v2.2.3 · Claude Opus 4.6 · 72 Requests · 3,328 Deltas

3.2×

Time Saved

3m 41s vs 11m 56s

1.8×

Cost Reduction

$2.02 vs $3.57

3.5×

Token Efficiency

1.2M vs 4.1M tokens

96%

Root-Cause Quality

of deltas traced to root cause

Without ReGradeWith ReGrade

Wall-Clock Time

Without ReGrade11m 56s
With ReGrade3m 41s−69%

Estimated Cost

Without ReGrade$3.57
With ReGrade$2.02−43%

Total Tokens

Without ReGrade4.1M
With ReGrade1.2M−71%

API Calls

Without ReGrade79
With ReGrade31−61%

Tool Calls

Without ReGrade48
With ReGrade16−67%

User Turns

Without ReGrade5
With ReGrade4−20%

With ReGrade's structured delta tools, Claude traced 96% of flagged deltas to a single root cause, using 71% fewer tokens and finishing 3.2× faster than raw replay.

Ghost CMS API benchmark: 72 requests, 3,328 deltas, 2 known bugs. Results describe this two-session comparison; evaluate performance and cost on your own workload.

Plan an evaluation

We will show you what ReGrade finds on a service you already run. Or start free: 10 replays and 100 MB every month, no credit card and no expiration.