concise-agent-prompts

Concise Agent Prompt Craft

General-purpose guidelines for writing prompt templates used by LLM agents in multi-step pipelines.

1 — The Litmus Test

Every line you write that enters an LLM context must pass one question: "Does the agent need this to decide what to do?" If no, cut it.

Only write what the agent needs to DO or KNOW to act correctly. Never include:

• Delivery meta-commentary — framing, transitions, or narration about the prompt itself (e.g. "You will now analyse…", "The following section covers…").
• Prompt-writer notes — rationale, caveats, or asides intended for a human reader rather than the executing agent.

2 — Defaults & Hygiene

• End every system prompt with a concise directive, e.g.: Be concise. No preamble, no summary, no template sections. (unless structured output is required downstream).
• Strip all filler: greetings, hedging phrases, meta-commentary about the task.
• If the prompt can be understood without a sentence, delete that sentence.

3 — Steer Scope, Not Quotas

• Never hard-code bullet counts, word limits, or truncation rules on model output. These are symptoms of an unclear scope.
• If output is too verbose → shorten and sharpen the prompt, not the output.
• If output misses a dimension → add it to the role description, not a checklist appended to the instruction.
• Regex-stripping or post-hoc trimming of model output is a code smell — fix the prompt first.

4 — Prefer Flowing Prose Over Structured Scaffolding

• Default output format for reasoning / analysis agents: short connected prose, not bullet inventories or category-labeled lists.
• Reserve numbered lists and structured schemas only for agents whose output is consumed by a parser or another agent.
• When you do need structure, specify the minimum structure required — every extra heading or field is a chance for the model to hallucinate filler.

5 — No Hard-Coded Limits or Examples in Prompts