TRAIL
Designing safe agents
Loops, tool contracts, permissions, and the spec that ties an agent together before it touches anything real.
An agent isn't a smarter chatbot — it's a model in a loop with tools that can take real, sometimes irreversible actions. This trail is the design discipline for that: what to grant it, what to gate, and how to write down the decisions before code makes them implicitly.
By the end you'll be able to scope an agent's tools and permissions to least privilege, place checkpoints where they actually catch a bad turn, and write the specification document that ties scope, access, and failure handling together.
Begin trail →- 1BuildAgent loops
Start with the mechanism: plan, act, observe, repeat. Understanding how a loop compounds an early mistake is what makes every later safeguard in this trail make sense.
- 2BuildTool contracts
Each action an agent can take is an API call with an unusual caller. Narrow, validated tool contracts bound what a wrong or manipulated call can do.
- 3BuildPermissions and least privilege
The safeguard that holds even when everything else fails: access the agent was never granted. Least privilege, applied for real.
- 4BuildPrompt injection defenses
Content an agent reads can carry instructions. The architecture — not a filter — is what keeps a followed instruction from becoming a real action.
- 5BuildDesigning human checkpoints
Not every step needs a human, but the irreversible ones do. Placing the checkpoint where it can actually catch something.
- 6BuildMCP and tool standards
A shared standard for connecting a model to tools, and why that also makes the whole thing easier to audit.
- 7BuildWriting an agent specification
The document that ties every earlier landmark in this trail together — scope, permissions, checkpoints, failure handling — before a single line of the agent runs.