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I Send Images Twenty at a Time — The Day the 21st Image Changed the Rules for the Other 61
Sending 62 images in one request failed with invalid_request_error. The cause was the image count, not the payload size. Here is how I recounted visual tokens as 28px patches and built batches that respect count, dimensions, and payload at once.
The agent I built in the Console could not be adopted by ant apply
ant apply refuses some drift and silently duplicates other resources. Here is where that line sits, why claude-lock.json belongs in your commits, and the five doors a second copy walks through.
Writing 25 as your session budget caps it at twenty-five cents
Managed Agents session budgets are expressed in minor units as a string. Here is how I mixed up the unit, hit budget_reached in minutes, and what raising versus clearing a budget actually does.
A 75% cheaper cache read moved one bill by 29% and another by 2.8%
Fable 5.1 and Mythos 5.1 changed the cache read multiplier from 0.1 to 0.025. Here is how to estimate your own saving from your token mix, and how to fix code that hard-codes the multiplier.
The translation read perfectly and still crashed at runtime
When you translate app strings with the Claude API, the meaning can be right while the format specifiers quietly break. Here is a severity-aware acceptance check and a repair loop that only re-translates the broken lines.
Don't Hand Your Agent the Tool That Commits — Sorting Tools Into Advise, Prepare, and Commit
Before you wrap irreversible actions in an approval gate, decide which ones never belong in the tool list at all. A three-tier inventory, a rewritten tool definition, and a small script that flags commits hiding in your schema.
The 400 that rejects a thinking block, and finding the edit that caused it
On Claude Fable 5.1, editing the system prompt, tools, or earlier messages before a thinking block makes the request fail with a 400. Here is how to check whether your own agent loop does that in a single request, and how to move a rebuilt system prompt and client-side trimming to patterns that leave the prefix untouched.
Read the Catalog Your CLI Already Ships Before Bulk-Replacing Model IDs
A newer generation makes older model IDs look stale. Here is how to pull the catalog embedded in your installed binary, sort every reference into matched, date-mismatched, and malformed, and stop the replacement that would break working IDs.
The September Price Increase for Sonnet 5 Isn't Happening. Rebuilding a Forecast I Got Wrong in July
Sonnet 5's introductory $2/$10 pricing was supposed to rise to $3/$15 on September 1. It won't. Here's how to recompute your own effective cost from the usage numbers you already have, with working code.
The listen Stream Kept Reopening Against My Serverless MCP Server
No errors anywhere, yet connections to the MCP server kept piling up overnight. Here is what happens when a fixed platform timeout meets a resubscribe loop, reproduced in a few dozen lines.
The Connection That Dies Mid-Thought Is Being Killed by Your Relay, Not the Upstream
Put a proxy or Worker in front of Claude Code and long thinking pauses start dying. The cause is neither the model nor the upstream — it is your relay holding the byte stream. Six relay behaviors compared side by side, plus how to verify yours before it ships.
Move the Prompt Tools API Into Your Own Scripts Before Workbench Closes on August 17
The legacy Workbench and three experimental prompt endpoints shut down on August 17, 2026. Here is how to count what actually depends on them, plus working local replacements for templatize_prompt and improve_prompt with real output.