Factory Droid vs Devin: agent against agent

Verdict and agent criteria

Ignore company size, contract terms, and platform architecture for the first pass. Give each agent the same repository state, task statement, permitted tools, acceptance tests, and human reviewer. Then compare the mechanics of the task loop. This prevents enterprise packaging from standing in for agent performance and prevents a benchmark from standing in for a production workflow.

From brief to approved plan

Droid Specification Mode starts from a short feature description. It analyzes the repository without changing files, generates acceptance criteria, implementation details, a file-level plan, tests, and security considerations, then waits. The developer can revise or approve the plan. Saving the approved output into .factory/docs turns the plan into a versioned artifact.

Devin begins with a task and forms a plan inside the session. It can ask questions, use Knowledge and Playbooks, inspect the configured environment, and update its approach as work proceeds. A good Devin task usually names the desired outcome, boundaries, relevant context, and verification. Cognition's guidance favors verifiable subtasks over broad instructions.

A generated plan is valuable only when the reviewer can reject it. Require the reviewer to check scope exclusions, data migration, compatibility, failure recovery, security-sensitive files, and verification commands. Approval should mean the plan is safe enough to execute, not that the prose looks complete.

Execution environment and continuity

Droid can work in the current local checkout, in CI, on a registered owned machine, or on a Factory-managed Droid Computer. A Droid Computer retains installed software, files, credentials, services, and configuration between sessions. The agent can return to a live development environment without paying setup cost every time.

Devin cloud sessions start from a configured virtual-machine snapshot. Repository onboarding defines how to clone, install, and prepare the environment. The session can use shell tools, an editor, and a browser. Devin CLI gives a fast local path, and /handoff sends conversation context plus the current branch to cloud execution when the job should continue away from the laptop.

Persistent state helps large monorepos, databases, emulators, and services. It also collects drift. Snapshot-based setup takes longer at session start and is easier to reproduce. Measure both setup success and repeated-run consistency. A fast second run on a dirty machine may conceal a missing bootstrap step.

Tools, models, and agent control

Droid can use shell commands, repository tools, MCP servers, skills, hooks, custom Droids, and SDK-provided controls. Organizations can limit model access, tools, commands, and network behavior. Factory Router can choose among models based on task and policy. Headless droid exec exposes autonomy settings and structured automation paths.

Devin uses shell, editor, browser, search, connected tickets, MCP integrations, Knowledge, and Playbooks. The product offers several frontier models alongside Cognition's SWE models. Devin sessions can be triggered from the web product, API, Slack, tickets, schedules, and local CLI. The agent experience remains consistent while the selected model can change.

Model diversity can improve resilience and complicate evaluation. Pin the model for the first comparison. Repeat the winning workflow with automatic routing or alternate models only after the agent loop has been measured. Otherwise a better model can hide a worse environment, and a cheaper route can hide extra review time.

Testing, evidence, and the pull request

Both agents can run tests and create commits or pull requests. The quality difference appears in evidence discipline. Require the agent to state what changed, why, which tests ran, which tests could not run, what assumptions remain, and where the riskiest code lives. Then verify selected evidence independently. A transcript claiming success is a lead for review, not proof.

Devin Review gives Cognition a dedicated pull-request product with diff analysis, bug finding, chat, code changes, and GitHub actions. It can become the review surface for changes produced inside or outside Devin. Droid can review code and automate PR analysis through its CLI and integrations, while Factory telemetry can record files, commits, pull requests, models, and tool activity.

Review burden belongs in the agent score. A correct 300-line diff with clear structure and evidence can be cheaper than a correct 80-line diff that mixes unrelated changes. Track first-review minutes, number of review rounds, percent of agent lines retained, and incidents after merge. Do not reward raw diff volume.

Failure modes

Droid's formal spec can reduce scope drift and can also formalize the wrong premise. Devin's managed session can reduce environment assembly and can also conceal what the snapshot supplies. Persistent computers can reduce setup cost and can also hide drift. Knowledge systems can reduce rediscovery and can also preserve stale facts. Every strength has an operational counter-control.

Price and accepted-task economics

Factory Pro costs $20 a month, Plus $100, and Max $200. Standard usage is constrained by rolling five-hour, weekly, and monthly windows. Droid Core and prepaid Extra Usage provide continued paths after standard capacity. Managed-computer access depends on plan and current terms.

Devin Free gives an individual a light allowance. Pro costs $20 a month, Max $200, and Teams starts at an $80 monthly minimum. Paid plans can use on-demand credits according to current account terms. Devin Review draws from a separate on-demand balance for AI review work.

For each task class, calculate subscription allocation, model or credit use, environment compute, human scoping, human review, rework, and expected incident cost. Divide by accepted tasks. Also report elapsed calendar time because asynchronous work can be valuable even when the dollar cost is similar. Keep failed tasks in the denominator.

When to pick each agent

Run four tasks before selecting: an undocumented bug, a specified feature, a repeated maintenance job, and a job with a private dependency. Use the same reviewer and acceptance standard. The set tests exploration, planning, repeatability, and environment access. Select a winner per class and identify the ownership cost of operating it.

Migration notes

Moving from Devin to Droid starts with exporting Knowledge, Playbooks, task templates, environment setup, secrets inventory, and accepted pull-request examples. Put durable facts in the repository. Convert repeat procedures into Factory skills, hooks, commands, or SDK workflows. Rebuild the environment on a Droid Computer or approved local target. Create a Specification Mode template for large tasks. Reproduce one pull-request workflow and telemetry trace before expanding.

Moving from Droid to Devin starts with saved specs, AGENTS.md, skills, headless commands, model rules, and computer setup. Convert stable facts into repository docs and selected Devin Knowledge. Convert procedures into Playbooks or automations. Create a Devin environment snapshot from versioned setup. Decide where local CLI work should use /handoff. Reproduce evidence and review requirements inside the session and Devin Review path.

Questions people ask

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