Source Intelligence
Sweep 28 Aug 2026 · 00:00Z Build v2.1.250 478 read Stable v2.1.236 Latest v2.1.250 Next v2.1.251 Feeds RSS JSON llms.txt
Reading a new release v2.1.251 Analysing changes · 2/5 Sorting the findings · 1/4 steps 470 findings $18.91 so far

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

Prompt capture

v2.1.203 system prompt

2 of 24 tool descriptions changed. Compared against v2.1.202.

Agent SDK, print mode 27 model strings 24 tools released captured Markdown

EnterWorktree +2 −2 of 36 lines

This edit reached all 27 arms

from line 25
 
 ## Entering an existing worktree
 
-Pass `path` instead of `name` to switch the session into a worktree that already exists (e.g., one you just created with `git worktree add`). The path must appear in `git worktree list` for the current repository  paths that are not registered worktrees of this repo are rejected. ExitWorktree will not remove a worktree entered this way; use `action: "keep"` to return to the original directory.
+Pass `path` instead of `name` to switch the session into a worktree that already exists (e.g., one you just created with `git worktree add`). On first entry from the launch directory, the path must appear in `git worktree list` for the repository that owns it — the current repository or, in a multi-repo workspace, a repository nested inside it; paths registered by neither are rejected. ExitWorktree will not remove a worktree entered this way; use `action: "keep"` to return to the original directory.
 
 Switching with `path` also works when the session is already in a worktree (the previous worktree is left on disk, untouched, and only the new one is tracked for exit-time cleanup), and from agents whose working directory was pinned at launch (subagent isolation or explicit cwd). In both cases the target must be a worktree under `.claude/worktrees/` of the same repository, and from a pinned agent the switch only affects this agent, not the parent session. After a further switch, previously-visited worktrees are no longer writable — re-issue EnterWorktree with `path` to return to one.
 
from line 32
 ## Parameters
 
 - `name` (optional): A name for a new worktree. If neither `name` nor `path` is provided, a random name is generated.
-- `path` (optional): Path to an existing worktree of the current repository to enter instead of creating one. Mutually exclusive with `name`.
+- `path` (optional): Path to an existing worktree to enter instead of creating one — of the current repository, or (on first entry from the launch directory) of a repository nested inside it. Mutually exclusive with `name`.
 

SendMessage +1 −1 of 14 lines

This edit reached all 27 arms

from line 11
 | `"researcher"` | Teammate by name |
 | `"main"` | The main conversation (background subagents only) |
 
-Your plain text output is NOT visible to other agents — to communicate, you MUST call this tool. Messages from teammates are delivered automatically; you don't check an inbox. Refer to active teammates by name; to address a background agent that has no name (or whose name a teammate holds)  or to resume a completed one  use its `agentId` (format `a...-...`) from its spawn result. When relaying, don't quote the original — it's already rendered to the user.
+Your plain text output is NOT visible to other agents — to communicate, you MUST call this tool. Messages from teammates are delivered automatically; you don't check an inbox. Refer to agents by name  names keep working after an agent completes (a send resumes it from its transcript). Use the raw `agentId` (format `a...-...`) from its spawn result only when the agent has no name, or when a newer agent took the name (latest wins). When relaying, don't quote the original — it's already rendered to the user.

The full text

The whole documents, one page each, exactly as they were sent.