Glossary · Agents and protocols
preflight
A check an agent runs against a site before it acts there: can it read, cite, connect to or transact with this domain, under the site's own published rules and its measured state. A preflight answers from evidence already gathered, so it costs the site nothing and takes well under a second; the answer is a signed decision receipt the agent can carry.
What preflight means
A check an agent runs against a site before it acts there: can it read, cite, connect to or transact with this domain, under the site's own published rules and its measured state. A preflight answers from evidence already gathered, so it costs the site nothing and takes well under a second; the answer is a signed decision receipt the agent can carry. It can tell an agent whether the action is permitted and how fresh that judgement is; it cannot guarantee the site will behave the same way a day later, which is why every receipt carries an expiry.
What preflight can and cannot support
| It can support | It cannot support |
|---|---|
| A check an agent runs against a site before it acts there: can it read, cite, connect to or transact with this domain, under the site's own published rules and its measured state. | A preflight answers from evidence already gathered, so it costs the site nothing and takes well under a second; the answer is a signed decision receipt the agent can carry. It can tell an agent whether the action is permitted and how fresh that judgement is; it cannot guarantee the site will behave the same way a day later, which is why every receipt carries an expiry. |
Where preflight comes up on this site
- 1,851 MCP servers from the registry: what they answer, and the one that tells the model to hide somethingPreflight gives one signed decision for the connect action on a domain, with the reasons, and the receipt stays with the action that followed it.
Terms this definition uses
Definitions that name preflight
decision receipt · receipt header
Related terms in Agents and protocols
How autonomous agents plan, remember, call tools and talk to each other, including MCP and A2A, and where each step can go wrong.
agentic web · decision receipt · receipt header · action assurance · resolve answer · freshness window · AI agent · Agent loop · Planner · Executor · Agent memory · Working memory · Long-term memory · Episodic memory · Semantic memory · Agent orchestration · Multi-agent system · Agent handoff · Delegation · Tool result · Tool schema · Tool description · Tool selection · Tool permission · Human-in-the-loop · Human-on-the-loop · Approval gate · Agent sandbox · Agent identity · Agent authorization · Agent discovery · Capability negotiation · MCP server · MCP client · MCP host · MCP resource · MCP prompt · MCP tool · MCP transport · JSON-RPC · A2A protocol · A2A client · A2A server · Agent skill · Agent task · Agent artifact · WebMCP · A2A
Questions about preflight
What is preflight?
A check an agent runs against a site before it acts there: can it read, cite, connect to or transact with this domain, under the site's own published rules and its measured state. A preflight answers from evidence already gathered, so it costs the site nothing and takes well under a second; the answer is a signed decision receipt the agent can carry.
What does preflight not show or guarantee?
A preflight answers from evidence already gathered, so it costs the site nothing and takes well under a second; the answer is a signed decision receipt the agent can carry. It can tell an agent whether the action is permitted and how fresh that judgement is; it cannot guarantee the site will behave the same way a day later, which is why every receipt carries an expiry.
Which area of the glossary does preflight belong to?
Agents and protocols: How autonomous agents plan, remember, call tools and talk to each other, including MCP and A2A, and where each step can go wrong.
← agentic web · decision receipt →
See it in the full glossary · 688 terms across 19 areas.