You can't prompt away a hallucination. You can validate it away.
A deterministic check on the agent's output, with one retry, kills a class of wrong answers no prompt rewrite reaches - and gives you a number, not a vibe.
Engineering Blog
Technical insights into multi-agent orchestration, local protocols, and
developer-centric terminal workflows.
A missing parameter is the agent asking what only you know.
When a tool call lacks a parameter, the agent's two instincts - fail or guess - are both wrong. Have the server elicit the missing field against a schema.
Three control axes are sitting in the MCP spec. Most teams use one.
An MCP server exposes resources, tools, and prompts - context the app pulls, actions the model takes, workflows the user invokes. Most teams wire only one.
The friction humans hate in pre-commit hooks is perfect for agents.
A git pre-commit hook turns 'the agent should run the tests' into 'the agent cannot commit broken code' - a deterministic gate that ships with every clone.
Gate three routes and the agent forgets the fourth. Make it one call.
Scatter gating logic inline and consistency depends on luck. Collapse the policy into one named helper, make calling it a rule, and enforcement is the default.
Stop describing your work to the agent. Hand it the diff.
Asking an agent to review what you say you did grades your spin, not your code. A small MCP server that reads the live diff grades reality instead.
If you can't reproduce the agent's failure, your fix is a guess.
Turn each reported agent failure into a committed synthetic scenario, then replay it headlessly on every change. The bug becomes a guardrail, not a patch.
Half your agent's 'hallucinations' never reached the prompt
Before you write another anti-hallucination instruction, split each wrong answer into a retrieval failure and a generation failure. They need opposite fixes.
If you can describe your workflow, it isn't a workflow - it's a habit.
The correction you keep re-typing into the chat is a missing command. Fold the recurring ritual into one parameterized verb backed by a rules file.
Your Reasoning Model Should Never Read Grep Output
Subagents are sold as parallelism. The real win is context hygiene plus model arbitrage: cheap explorers read, and your expensive model sees only findings.