Entity trail

Composer 1.5

Source-backed findings, relationship evidence, citations, and briefing history from the public MindPattern archive.

Briefing refs

Findings

Edges

Sources

Corpus findings

2026-06-29 / skill-finderCursor Composer 2's compaction-in-loop RL cuts mid-task 'forgot the constraint' errors ~50%Composer 2 (released March 19, 2026) trains the model to compress its own ~200K context down to roughly 1,000 tokens mid-session and continue — and because the compression happens inside the RL loop with a reward for maintaining task completion post-compression, the model learns which details to keep, reporting ~50% fewer compaction errors than external summarization. The practitioner signal: 'compaction-in-the-loop' is becoming the differentiator for multi-hour autonomous coding, and external bolt-on summarizers are the weak point. Builders evaluating coding agents for long refactors should test specifically for constraint loss after compression, not just raw context size.
2026-06-27 / reddit-researcherCursor's June Update: Composer 2.5 Powers Bugbot (~90s Reviews), Pre-Push '/review', and Always-On AutomationsCursor's June release ties its in-house Composer 2.5 model to Bugbot, cutting average review time from ~5 minutes to ~90 seconds while finding ~10% more bugs per review (0.62 vs 0.56) at ~22% lower cost per run. A new /review flow runs Bugbot and Security Review before push, dedups against the eventual PR, and supports incremental 'only what's new' review; Cursor also added Automations — always-on agents plus an /automate skill with GitHub/Slack triggers and computer use. This is a concrete move from chat-IDE to standing review/automation agents in the dev loop.
2026-05-26 / rss-researcherCursor Composer 2.5 Promotional Period Ends — Fast Tier Price Doubles to $3/$15 per Million TokensCursor's promotional double-usage period for Composer 2.5 ended May 25, and the new pricing reveals a significant cost increase on the Fast tier (the default): $3.00/$15.00 per Mtok input/output, up from $1.50/$7.50 in Composer 2. Standard tier pricing held at $0.50/$2.50 per Mtok. Since Fast is the default option most developers use, the effective cost of daily Cursor usage has roughly doubled — a notable development alongside Uber's report of unsustainable AI tooling costs.
2026-05-25 / vibe-coding-researcherPattern: AI Coding Model Commoditization — Open-Weight Fine-Tuning Matches Frontier at 1/10th CostCursor's Composer 2.5 proves the commoditization thesis: take an open-weight base (Kimi K2.5, 1T params), fine-tune on proprietary session data, and match Opus 4.7 on SWE-Bench at $0.50/M input tokens vs. $15. Google takes a different route with Gemini 3.5 Flash at 4x speed. The pattern: raw coding capability is no longer a moat — distribution, data flywheel, and agent orchestration are. Builders should expect pricing pressure across all AI coding tools through Q3 2026.
2026-05-25 / vibe-coding-researcherCursor Ships Composer 2.5 — In-House Model Built on Kimi K2.5 Matches Opus 4.7 at 1/10th the CostCursor released Composer 2.5 on May 18, a coding model fine-tuned on Moonshot AI's open-weight Kimi K2.5 (1T total params, 32B active MoE) using real-time session data from millions of Cursor users. It hits 79.8% on SWE-Bench Multilingual — matching Opus 4.7 — while pricing at $0.50/M input tokens vs. $15 for frontier models. The Agent Swarm feature decomposes tasks into up to 100 parallel sub-agents with a 1,500 tool-call budget per workflow.
2026-05-23 / agents-researcherCursor Ships Composer 2.5: Custom Agentic Model Hits 79.8% SWE-bench Multilingual at 10-60x Lower Cost Than Frontier ModelsCursor released Composer 2.5 on May 18, its own agentic coding model trained with 25x more synthetic tasks than Composer 2 and a novel targeted textual feedback approach. It scores 79.8% on SWE-bench Multilingual (within 1 point of Opus 4.7, ahead of GPT-5.5) and ranks 3rd on the Artificial Analysis Coding Agent Index at $0.50/$2.50 per million input/output tokens — 10-60x cheaper than the two models above it. The update also adds full-screen agent tabs, a floating prompt bar, and configurable tool call density.
2026-05-21 / skill-finderCursor Composer 2.5 Ships with Substantially Improved Long-Running Task Intelligence and Complex Multi-Step Instruction FollowingReleased May 18, Composer 2.5 is Cursor's model upgrade specifically targeting the failure modes of extended agent sessions: losing context mid-task, misinterpreting compound instructions, and degrading quality on long-running work. Cursor claims 'substantial improvement in intelligence and behavior' with better sustained work quality. Combined with the earlier Cursor 3.0 parallel agent architecture, this makes Cursor's agent mode meaningfully more reliable for the multi-file refactors and feature implementations where previous versions would drift.
2026-04-22 / vibe-coding-researcherTip: Agent Skills Matter More Than Model Choice — 880-Eval Benchmark Shows Haiku 4.5 + Skill Beats Baseline Opus 4.7Tessl ran 880 evaluations across 9 models (Opus 4.7, Opus 4.6, Sonnet 4.6, Haiku 4.5, three Codex variants, Cursor Composer-2) with and without agent skills. Result: Haiku 4.5 with a skill scored 84.3%, beating baseline Opus 4.7 at 80.5%. Haiku's 23.1-point lift was the largest of any model. With skills loaded, the frontier models converge: Opus 4.7 (94.5%), Opus 4.6 (93.8%), Sonnet 4.6 (93.3%) — within 1.2 points. Takeaway: invest in skill engineering before upgrading models.
2026-04-18 / skill-finderCursor 3 Ships Composer 2: Anysphere's Own Frontier Coding Model at 200+ tok/s, BugBot Hits 80% Resolution Rate, Design Mode Adds Figma-Style UI CanvasCursor 3 (April 2) is Anysphere's biggest release: Composer 2 is a frontier model pretrained from scratch on curated code, then RL-trained against tool-use tasks, priced at $0.50/$2.50 per million tokens. BugBot now learns from PR feedback to create review rules, with resolution rate nearing 80% — 15pp ahead of nearest competitor. Design Mode adds a Figma-style canvas where dragging a component generates JSX and Tailwind. April 13 update added tiled layout and voice input to the Agents Window.
2026-04-03 / skill-finderCursor 3 Composer 2 Model: Fine-Tuned Kimi K2.5 Beats Opus 4.6 at 10x Lower Cost — $0.50/M Input TokensCursor's Composer 2 model, shipping with Cursor 3, is a fine-tuned variant of Moonshot's Kimi K2.5 that scores 61.7 on Terminal-Bench 2.0 and 73.7 on SWE-bench Multilingual — beating Opus 4.6 on coding benchmarks while costing $0.50/M input and $2.50/M output (roughly 10x cheaper than Opus, 5x cheaper than GPT-5.4). Composer 2 Fast delivers output at $7.50/M vs GPT-5.4 Fast's $75/M. Demonstrates that fine-tuned open models can compete with frontier models on domain-specific tasks at dramatically lower cost.
2026-03-27 / agents-researcherKlaviyo Ships Composer and Expands Customer Agent: Autonomous B2C CRM Builds Launch-Ready Omnichannel Campaigns from Single PromptsKlaviyo launched Composer, an agentic AI experience that builds launch-ready omnichannel marketing campaigns from a single natural-language prompt, grounded on 14+ years of marketing intelligence and billions of consumer interactions from 193K customers. New Customer Agent retail skills include order tracking, returns/exchanges, subscription editing, and loyalty lookup with Agent Guidance for brand-controlled voice, tone, and escalation rules. Over 75 platform features shipped alongside, signaling the autonomous CRM category is real and shipping.
2026-03-25 / skill-finderCursor Composer 2 Built on Kimi K2.5: Self-Summarization Enables Hundreds of Sequential Actions, 61.3 CursorBench (44.2→61.3), $0.50/M Input TokensCursor revealed Composer 2 on March 19, confirming March 20 it's built on Moonshot AI's open-source Kimi K2.5 with continued pretraining and RL. Key innovation: self-summarization training lets it compress and retain context beyond window limits, enabling hundreds of sequential actions without coherence loss. Benchmarks: CursorBench 61.3 (up from 44.2), Terminal-Bench 2.0 61.7 (beats Claude Opus 4.6's 58.0, trails GPT-5.4's 75.1), SWE-bench Multilingual 73.7. Standard at $0.50/M input tokens; fast variant at $1.50/M is the default.

Graph relationships

BENCHMARKED AGAINST
Sonnet 4.5
Composer 1.5 outperforms Sonnet 4.5 on Terminal-Bench.
Source finding
RELEASED
Cursor
Cursor released Composer 1.5 with improved RL scaling.
Source finding
RELEASED
Cursor -> Composer 1.5
Cursor released Composer 1.5 with improved RL scaling.
Source finding

Source trail

Cursor Blog Cursor Changelog — Composer 2.5 Cursor Blog Tessl Cursor Blog — Meet the New Cursor VentureBeat — Cursor's Composer 2 Beats Claude Opus 4.6 Klaviyo

Graph sources

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