Changelog

API updates and version history

This changelog documents all changes to the Caesar API. We follow date-based versioning, where each version represents a stable snapshot of the API.

Versioning approach

Caesar uses Stripe-style date-based versioning. Each version is a dated snapshot that remains stable indefinitely. You can pin your integration to a specific version and upgrade on your own schedule.

Set your API version using the API-Version header or pin it to your API key in the dashboard.

November 27, 2025

Renamed compute_units to reasoning_loops

The compute_units parameter has been renamed to reasoning_loops to better reflect what the parameter controls. This is a breaking change for request payloads.

Before (2025-08-08)
1{
2  "query": "What is the current price of Bitcoin?",
3  "compute_units": 3
4}
After (2025-11-27)
1{
2  "query": "What is the current price of Bitcoin?",
3  "reasoning_loops": 3
4}

New request parameters

Five new parameters give you finer control over research behavior:

ParameterTypeDefaultDescription
collection_idsarray-IDs of collections to search across
source_timeoutinteger60Maximum seconds to wait for each source
reasoning_modebooleantrueEnable multi-step reasoning
allow_early_exitbooleantrueAllow completion before max loops if sufficient information gathered
exclude_socialbooleanfalseExclude social media sources from research

Collection-based research

You can now associate research requests with file collections using the collection_ids parameter. The research pipeline will search across all files within the specified collections.

1{
2  "query": "Summarize the key findings from my research papers",
3  "collection_ids": ["a1b2c3d4-5678-90ab-cdef-1234567890ab"],
4  "reasoning_loops": 3
5}

Combine collection_ids with files to include both collection-based and individual file sources in a single request.

New response fields

Two new fields provide better visibility into job execution:

FieldTypeDescription
reasoning_loops_consumedintegerActual loops used (for billing)
running_timefloatTotal execution time in seconds

Billing is based on reasoning_loops_consumed, not reasoning_loops. If your job completes early, you only pay for actual usage.

Removed fields

The score field has been removed from result items. Source relevance is now determined internally and reflected in result ordering.

Migration guide

  1. Replace compute_units with reasoning_loops in all requests
  2. Update response parsing to use reasoning_loops_consumed instead of compute_units_consumed
  3. Remove any logic that depends on the score field in results
August 8, 2025

Initial API release

The first public version of the Caesar Research API.

Core features

  • Research endpoint: POST /research for creating research jobs
  • Streaming support: Server-sent events for real-time progress updates
  • OpenAI compatibility: Drop-in compatible endpoints at /compat/completions and /compat/chat/completions

Request parameters

ParameterTypeDefaultDescription
querystringrequiredThe research question
compute_unitsinteger3Number of reasoning iterations
autobooleanfalseEnable automatic parameter selection

Response fields

Each completed research job returns:

  • answer: The synthesized research response
  • results: Array of source citations with URLs and excerpts
  • compute_units_consumed: Actual units used for billing