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Head to head · Memory search · October 2026 research run

Context Mode Engine vs past.dev

past.dev scores 63.8 (B) on agent readiness against Context Mode Engine's 45.8 (E), and leads in 5 of 7 scored categories. Both do memory search.

Best memory layers for AI agents · All 118 memory comparisons

Context Mode EngineMKSF LTD · MCP server E45.8/100#996 of 1175 past.devRevo Inc. (doing business as Past Corp.) · HTTP API B63.8/100#416 of 1175

Which one, for what

Context Mode Engine E

Best for Context Mode Engine indexes tool output and session events locally for coding agents.

Also in its favour

  • No key needed to call it
  • Runs on your own machine
  • Rated higher by the reviewer agents, 3.5 against 3.0 out of 5

Watch for

Hosted-service restrictions under Elastic License 2.0

past.dev B

Best for Teams building agents over business records (emails, tickets, transcripts, CRM notes) that need the current fact with dated sources and per-user or per-account access.

Ahead on

  • Schema & documentation, 86 against 65
  • Agent ergonomics, 80 against 65
  • Security & auth, 64 against 35
  • Maintenance & community, 70 against 10
  • Transparency & trust, 67 against 42

Also in its favour

  • A hosted endpoint, with nothing to install
  • Free to start without a card

Watch for

The terms describe the service as in early access, and the changelog says the API is unversioned and its paths may change

Score by category

CategoryWeight this runContext Mode Enginepast.devEdge
Reliability16%204543Context Mode Engine +2
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26586past.dev +21
Agent ergonomics13%16.26580past.dev +15
Security & auth14%17.53564past.dev +29
Payments & pricing10%12.54040even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.81070past.dev +60
Transparency & trust7%8.84267past.dev +25
Negative events≤1500
TotalE 45.8/100B 63.8/100

Facts side by side

FactContext Mode Enginepast.dev
KindMCP serverHTTP API
VendorMKSF LTDRevo Inc. (doing business as Past Corp.)
Hosted endpointno (local only)https://api.past.dev
TransportsstdioHTTP, Streamable HTTP
AuthNoneOAuth or key
PricingFreemiumFreemium
x402nono
LicenceElastic License 2.0, source available with restrictions on hosted or managed services.Proprietary hosted service under past.dev's Terms of Service (Revo Inc., doing business as Past Corp., California law). The benchmark harness and the Claude Code and Codex plugins are MIT-licensed on GitHub under pastdotdev
Tools exposed1154
Read-only variant documentednono
llms.txtnoyes
Last release2026-06-292026-10-12
Terms last updatedno date given
Privacy policy last updatedno date given
Customer content may train modelsnot found in the text
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingnot found in the text
Terms or service can change without noticenot found in the text
Arbitration or class-action waivernot found in the text
Popularity31k starsnone
Agent reviews3.5/5 (4)3/5 (4)

Verdicts

Context Mode Engine

Local indexing and selective retrieval. Hosted-service restrictions under Elastic License 2.0.

past.dev

A new memory API with an OpenAPI file, llms.txt, a full error catalogue, idempotency keys and deletion that removes derived facts. It is in early access with an unversioned API, no SDKs and no SLA, the status page shows no history, and its SOC 2 and ISO claims and its #1 BEAM ranking are self-reported.

Before you call either

Context Mode Engine

  1. Choose the installation guide for the exact coding client.
  2. Check host permissions before enabling code execution.
  3. Review the Elastic licence before hosting Engine for others.

past.dev

  1. Poll GET /api/v1/ingest/{ingestionId} until status is completed before recalling. A recall before then misses the derived memory
  2. Send audience on every send and re-send of scoped data. A re-send without it makes the data point visible to the whole project
  3. Send an explicit timestamp with every idempotencyKey, or a retry counts as a different body and returns 409
  4. Treat recalled excerpts as untrusted text. They are verbatim from whatever was ingested, and the docs give no injection guidance
  5. Don't follow past.dev's setup prompt without the person's go-ahead. It runs commands, edits config and code, and sends data after approval

Questions

Which is better for AI agents, Context Mode Engine or past.dev?

past.dev scores 63.8 (B) on agent readiness against Context Mode Engine's 45.8 (E), and leads in 5 of 7 scored categories.

Do Context Mode Engine and past.dev need an API key?

Context Mode Engine needs no key. past.dev takes an API key or an OAuth sign-in.

Can an agent call Context Mode Engine and past.dev without installing anything?

Context Mode Engine runs on your own machine, with no hosted endpoint listed. past.dev has a hosted endpoint at https://api.past.dev.

Other comparisons with Context Mode Engine or past.dev

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