All Articles
The MCP Server Connects Fine and Still Hands Back Zero Tools — Catching Silent Capability Drift with a Tool Manifest Diff
A missing credential does not break the MCP handshake. initialize succeeds, tools/list succeeds, and the array comes back empty. Here is the measured behaviour, and a preflight that locks the expected tool surface and fails closed before the agent ever starts.
Whose Environment Expands That Variable? Fingerprinting Your Effective Managed MCP Policy
Variable references in the Managed MCP allowlist and denylist now resolve from the startup environment and the managed-settings env block. I rebuilt both resolution orders locally to see where verdicts diverge, then wrote a preflight check that reduces the effective policy to a comparable fingerprint.
Locking down Claude Code sandbox egress with strictAllowlist
Tightening automation egress with strictAllowlist in Claude Code v2.1.219, plus measured failure timings that tell a policy deny from DNS and real outages, and three defects that made my own recon scripts return nothing.
A Committed Symlink That Points Outside the Worktree — Auditing Repos Before You Let AI Spin Up Parallel Trees
Claude Code 2.1.212 fixed a bug where a committed symlink under .claude/worktrees could be followed during worktree creation and write outside the repo. The patch closes the following side. Here is an audit script for the committed side, plus a quarantine workflow.
I Could No Longer Remember What I'd Changed in Auto Mode — Where claude auto-mode reset Fits In
Running nightly automation for weeks, I kept nudging my auto-mode settings one at a time. One morning a small oddity made me realize I could not recall what I had changed. Here is how I rebuilt my configuration around claude auto-mode reset as a known-good baseline, from a solo developer's field notes.
I Stopped the Headless Claude Code Job, but the Build Kept Running — Designing Teardown Around exit 143
In headless mode, a SIGTERM received while Claude Code was mid-Bash used to orphan the command's process tree. The 2.1.212 fix changes that to a clean exit 143. Here is how to redesign your supervisor and cleanup around that contract.
I Believed Plan Mode Only Read — Replacing That Belief With Machinery
Claude Code 2.1.212 fixed a bug where plan mode ran file-modifying Bash commands without the permission prompt or the SDK canUseTool callback. Here is what could happen while that assumption was broken, how to verify your own setup, and how to stop leaning on a mode name for safety.
Branch with /fork, Delegate with /subtask — Two Commands That Traded Jobs
In Claude Code 2.1.212, /fork now clones your conversation into a background session, and in-session subagents moved to /subtask. Here is how I decide between them, and the budgets worth setting before you start branching freely.
The MCP Server I Declared Vanished from the List — Designing Config for a Namespace You Share with the Vendor
When a vendor reserves an MCP server name, your .mcp.json declaration goes quiet instead of failing. Here is the preflight check and prefix convention I use to turn that silent gap into a loud stop before an unattended run.
The String I Approved Wasn't the String I Read — Testing a Relayed Permission Prompt with Deceptive Characters
I pushed bidi overrides and zero-width characters through my own approval relay. NFKC normalization caught 0%. Here is why, and the implementation that catches 100% with zero false positives.
My Nightly Subagents Ran, and I Couldn't Retrace Them — Trimming the Logs That --forward-subagent-text Unleashed
Subagent text and thinking can now flow into stream-json output, and unattended log volume climbs sharply with it. Here are measured numbers, a three-tier retention filter that keeps only what postmortems need, and a correlation ID design that survives missing fields.
The Morning My Table Ended in "… 2,847 more rows" — Separating Render Caps from Token Cost in Tool Output
Claude Code 2.1.209 caps markdown tables at 200 rows plus a remainder count. Only the rendering is capped — the model still receives every row. Here is how to measure the gap and redesign tool output around aggregates.