Claude Haiku 5.5

In a project, with and without ludion sync

This model has no run in a project yet.

Without tools

Measured on Oct 11, 2026, 2 days ago.

Lessons it misses without tools

• wrangler >=4.122.0 changed the default of `nodejs_compat`. With a compatibility date of 2026-08-04 or later it is on; to turn it off, remove the positive flags and add both no_nodejs_compat and no_nodejs_compat_v2. Silent: code written for older versions still runs, without an error. wrangler
• wrangler >=4.124.0 changed what `--latest` does. It uses the latest compatibility date supported by this version of Wrangler. Silent: code written for older versions still runs, without an error. wrangler
• wrangler >=4.121.0 added `--jurisdiction us`. Create a D1 database in the US jurisdiction with wrangler d1 create and --jurisdiction us. Older versions don't have it. wrangler
• wrangler >=4.118.0 changed the default of `X_LOCAL_OBSERVABILITY`. wrangler dev now captures request traces and console logs into the Local Explorer Observability tab; set X_LOCAL_OBSERVABILITY=false to opt out. Silent: code written for older versions still runs, without an error. wrangler
• wrangler >=4.145.0 renamed `wrangler r2 sql` to `wrangler basin sql`. Previous command paths remain available as hidden compatibility aliases. Silent: code written for older versions still runs, without an error. wrangler
• wrangler >=4.127.0 added `workflows[].concurrency.limit`. The limit is the maximum number of Workflow instances that can run concurrently. Older versions don't have it. wrangler
• wrangler >=4.125.0 added `connect`. Configure connect with protocol tcp and a port to receive raw socket connections during wrangler dev in the Worker connect(socket, env, ctx) handler. Older versions don't have it. wrangler
• wrangler >=4.117.0 renamed `/cdn-cgi/handler/scheduled` to `/cdn-cgi/local/scheduled`. wrangler dev and the Vite plugin transparently rewrite the old paths to the new ones, meaning you can continue to use the old paths. Silent: code written for older versions still runs, without an error. wrangler
• wrangler >=4.148.0 changed what `wrangler versions secret bulk` does. Set a secret value to null in JSON input to remove it from the new Worker version. Silent: code written for older versions still runs, without an error. wrangler
• agents >=0.27.0 added `npx agents tui`. It is a terminal client for a conversation's Web Channel. Older versions don't have it. agents
• agents >=0.24.0 added `transport`. useAgent speaks the Agent protocol over one of two wires: cf-websocket (the default, a hibernating WebSocket) or the experimental capnweb transport. Older versions don't have it. agents
• agents >=0.23.0 deprecated `subAgent()`; use `this.dynamicAgents.get()` instead. subAgent(), hasSubAgent(), listSubAgents(), abortSubAgent() and deleteSubAgent() still work, delegate to this.dynamicAgents, and are deprecated in place. Silent: code written for older versions still runs, without an error. agents
• agents >=0.22.0 changed what `Agent` does. Agent now directly extends Cloudflare's DurableObject, with the required PartyServer runtime vendored into agents/lifecycle. Silent: code written for older versions still runs, without an error. agents
• agents >=0.22.0 changed the default of `throttle`. useAgentChat now coalesces updates every 50ms; pass throttle: false to render every chunk as it arrives, or a number to change the interval. Silent: code written for older versions still runs, without an error. agents
• agents >=0.22.0 added `Scheduler`. Scheduler, under agents/schedules, is a reusable Lifecycle capability for persistent delayed, dated, cron, and interval callbacks. Older versions don't have it. agents
• agents >=0.20.0 changed what `createMcpHandler` does. A function input to createMcpHandler is always treated as an SDK v2 factory, so concurrent Worker requests receive isolated server instances. Silent: code written for older versions still runs, without an error. agents
• agents >=0.20.0 changed what `MCPClientConnection` does. MCPClientConnection probes for stateless MCP with server/discover, then falls back to the legacy initialize handshake on the same connection when needed. Silent: code written for older versions still runs, without an error. agents
• vitest >=5.0.0 changed what `toHaveTextContent` does. The browser-mode matcher now validates that the text content is exactly equal to the expected string; toMatchTextContent performs a partial match. vitest
• vitest >=5.0.0 changed the default of `--merge-reports`. By default, Vitest stores all blob test results in .vitest/blob/, so they can be later merged using --merge-reports. Silent: code written for older versions still runs, without an error. vitest
• vitest >=5.0.0 changed what `-t` does. The pattern is matched against the full name: the enclosing suite names and the test name joined with ' > ' (the same string shown in the reporter output). Silent: code written for older versions still runs, without an error. vitest
• vitest >=5.0.0 changed the default of `extends`. Projects defined with an inline configuration inherit options from the root-level configuration. Silent: code written for older versions still runs, without an error. vitest
• vitest >=5.0.0 added `vi.when`. vi.when takes a spy and lets you define argument-specific behaviors. Older versions don't have it. vitest
• vitest >=5.0.0 added `--repeats`. It repeats every test regardless of the result, which is useful for hunting flaky tests. Older versions don't have it. vitest
• vitest >=5.0.0 added `-p`. It is a shorthand for the --project filter. Older versions don't have it. vitest
• vitest >=5.0.0 changed what `vitest list` does. It parses test files statically instead of running them to collect tests; pass --no-static-parse to run the files instead. Silent: code written for older versions still runs, without an error. vitest
• wrangler >=4.121.0 changed what `DO_NOT_TRACK` does. Wrangler disables telemetry when DO_NOT_TRACK=1 is set, regardless of other telemetry settings. Silent: code written for older versions still runs, without an error. wrangler
• wrangler >=4.141.0 changed the default of `durable_objects.code_update_strategy`. When unset, the strategy defaults to deferred with a 5-minute maximum delay; configure mode and max_delay to set it. Silent: code written for older versions still runs, without an error. wrangler