Cursor Agent SDK vs Mastra

Cursor Agent SDK 45

Local-package reading, since the owner runs the framework, with Cursor's hosting as an option. Official npm package with Node 22.13 or newer stated in engines and in the docs, which also say never Bun (20). Closed source, so no public CI or test suite (0). No public issue tracker. github.com/cursor/cursor holds a README and SECURITY.md, and forum.cursor.com has no Agent SDK tag, so there's nothing to count open crashes against. The troubleshooting page lists known failures with fixes (5). A dated changelog of two entries, 0.2.29 and 0.3.0, both 23 October 2026, and 0.3.0 calls out the removed persistent option, but the 27 earlier @cursor/bdk versions and 123 @cursor/july versions have no notes, and one build ships under three package names (5). Version 0.3.0, but the changelog post of 20 October says generally available and the docs changelog labels 0.3.0 the GA release, which we read as declared stable (15). 20+0+5+5+15 = 45.

Mastra 87

Official npm packages, Node 22.13 or newer (20). Public CI workflows for unit, store, workspace and e2e tests; on 6 November the newest runs on main (Version Packages, Trigger Cloud Integration Tests) succeeded, while the test workflows themselves run on pull requests (22). 436 open issues and 795 open issues and pull requests on 6 November from GitHub's API, with 2,077 issues opened in the 90 days to 3 November; all 50 newest had a comment and 24 were closed, with issue-triage automation (18). A changesets CHANGELOG per package, a CI gate that needs approval for any major bump and migration guides, but no written versioning policy found, and .network() is deprecated without a removal date (12). 1.82.0 (15). 20+22+18+12+15 = 87, up from 74 on 6 October, when GitHub couldn't be read.

Cursor Agent SDK 30

Framework reading of the published rubric. No payment protocol (0). Per-million-token prices for Cursor models, including the default Grok 4.5 with Fast, and plan prices are public, but no price for managed hosting and no statement of which plans cover the Agent SDK were found (15). The package is free and the Free plan needs no card, but its usage is only described as limited agent requests (15). A person signs in through a browser or creates an API key in the dashboard before a model turn runs (0). 0+15+15+0 = 30.

Mastra 60

No payment protocol (0). Scored on the hosted platform, whose per-unit prices are public without a login ($10 per 100K observability events and $0.35 a CPU hour on Starter) (20). The Apache 2.0 packages install with no card (20) and no account, and run any model (20).

Cursor Agent SDK 74

0.3.0 on npm on 25 October 2026, per the 27 October check (npm not re-read on 2 November), and the docs changelog still ends at 0.3.0 of 23 October (30). Five @grok/agent-sdk versions from 22 to 25 October and 29 @cursor/bdk versions since 22 September, per the 27 October check (20). Closed product. A public changelog with two entries and a forum with no Agent SDK tag, so we couldn't see replies to SDK reports (8). The npm package is current and official, TypeScript only (12). Dependencies are current releases, but there's no public CI and the same build goes out under three names with a postinstall script (4). 30+20+8+12+4 = 74.

Mastra 96

@mastra/core 1.82.0 on 2026-11-04 (30). 27 stable releases in the 90 days to 6 November, 8 of them since 6 October (20). 436 open issues on 6 November, all 50 newest issues commented and 24 of them closed (22). Client, MCP and store packages are current, and @mastra/mcp 1.x stays supported beside 2.x (15). Renovate and CI configured, with the newest runs on main passing (9). 30+20+22+15+9 = 96.

Cursor Agent SDK 82

Framework reading. Typed TypeScript declarations ship in the package, tools take Zod or JSON Schema, agent-sdk help --json describes every command's flags and exit codes, and GET /v1/info and GET /v1/tools/:name return the discovered surface and each tool's schemas. No OpenAPI document for the HTTP routes (20). cursor.com/llms.txt lists every Agent SDK page with a Markdown twin, and the package ships the docs and an llms.txt (10). The overview has a table of when to use the Agent SDK, Automations or Grok Bot, and the hooks page has a table of what to use instead of a hook for each job (18). Typed config, effect as an enum or predicate, timeArgs checked against the input schema, and slug patterns stated (13). Examples on every page, with error tables for direct tool calls, HTTP 401, 403 and 409, the limit error's JSON and seven exit codes (15). A dated changelog, but only two entries, both from 23 October 2026 (6). 20+10+18+13+15+6 = 82.

Mastra 98

Typed TypeScript API with a reference section (25). llms.txt with a when-to-use list and condensed instructions for coding agents (10). The docs say when to use durable agents, and point multi-agent users from .network() to supervisor agents (20). Tools take Zod schemas (15). Examples on every page, and MastraError with ids and categories documented, though errors are spread across pages (13). Per-package changelogs and migration guides (15).

Cursor Agent SDK 80

Framework reading, scored on what it takes to run a tool-calling agent with MCP. One file per tool and one file per MCP connection, tools and disallowedTools filters with effects: "read", and an allowlist for the harness's built-in tools (22). Concurrency caps with queued turns, --fields, page tokens and limits on list commands, and a per-session cost view. We found no turn cap or spend cap for a run (12). Built-in routes return { ok: false, error } codes, direct tool calls have documented 400, 404, 409 and 500 codes, and the CLI has seven exit codes (18). Reads and idempotent calls retry up to three times, writes run once, MCP readOnlyHint and idempotentHint decide retries for connection tools, and dry-run sessions stub writes (20). agent-sdk init scaffolds a working project and every agent field is optional, but the framework is TypeScript only (8). 22+12+18+20+8 = 80.

Mastra 92

An MCP client in about ten lines with listTools() for static or listToolsets() for per-request tools, and ToolSearchProcessor for loading tools on demand (25). Step limits, memory windows and processors such as a token limiter control what reaches the model (20). MastraError with ids and categories, and processors can abort with a reason the caller can read (17). Workflow step retries, snapshots and durable agents for resuming (20). create-mastra scaffolds a project and the model router takes a plain string, but it's TypeScript only (10).