TDD with an agent: the test pays, the ritual does not
AI tests detect 69% of faults against 17.2% for humans, with lower coverage. The TDD flow inside the agent made no difference and cost up to 8.5× more.
- tdd
- testing
Building agents that survive production: tools, verification, context, guardrails and telemetry, with every figure traced to a primary source.
AI tests detect 69% of faults against 17.2% for humans, with lower coverage. The TDD flow inside the agent made no difference and cost up to 8.5× more.
The best model solves 80% of browser tasks. Declaring the tool costs 6,600 tokens, and the docs' security checklist is longer than the usage one.
Anthropic measured a 90.2% gain with multi-agent and, in the same text, advised against it for coding. The rule that decides, and the 15× cost.
Three things compete for the memory, not one. The KV cache formula, the budget by RAM tier and why quantizing fails to solve long context.
Only 37% of organizations can revoke an AI agent's credentials. And 88% had an agent incident in the last year.
A 1-hour cache used twice still loses money. The break-even arithmetic, the official multipliers and the leaks your dashboard never shows.
Long context scored 73.1% against RAG's 65.4%, at 26 times the cost per query. The measured boundary, and why the right answer is routing.
MCP connects the tool, A2A connects agents, WebMCP connects the site. What each solves, the real state of each, and what none of them expresses.
Across 18 models tested, performance falls as the input grows, before the window fills. The four pillars for keeping context small.
Memory cut the steps from 20 to 5 in a Databricks study. And it made the agent repeat its own error with more confidence. What to keep and what to delete.
89% of teams instrumented their agents and only 52% evaluate. How to build a test set, choose a threshold and put the gate in CI without false alarms.
An LLM judge agrees with humans as much as humans agree with each other, and errs in measured ways: the authorship label alone moves the score by 0.43 points.
Of the documented agent failures, 40 out of 52 were preventable by harness layers. Where to put the lock and why a classifier is not enough.
An agent bug does not reproduce: the trace has to exist before the error. The span tree, the OpenTelemetry attributes and what is still moving.
With 10 tools the agent gets everything right; with 107 it fails outright. How to design tools an agent uses well, with before and after.
Asking "are you sure?" makes the model switch answers in 46% of cases and lose 17 points. The bottleneck is finding the error, not fixing it.
Harness engineering explained: why LangChain climbed 25 places without changing the model, the five layers, and what decides a long task.
The official OWASP Top 10 list for AI agents, from ASI01 to ASI10, with the real, dated incident that has already exploited each of the ten risks.
Twelve prompt injection defenses reporting near-zero rates were broken above 90%. Why the problem is structural and what reduces risk.