Glossary
Signature-Agent header
In short
The request header in Web Bot Auth that names the URL of the signer's key directory, telling the site where to fetch public keys. Log it on every request: it is the only field that tells you which key directory to fetch. Example: ChatGPT's Cloud browser sends Signature-Agent: "https://chatgpt.com". Related: Verify Web Bot Auth signatures and ChatGPT agent profile.
Definition
The request header in Web Bot Auth that names the URL of the signer's key directory, telling the site where to fetch public keys.
Sourced example
ChatGPT's Cloud browser sends Signature-Agent: "https://chatgpt.com". Source, read 2026-11-04.
How it shows up here
Log it on every request: it is the only field that tells you which key directory to fetch.
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Sources
Last reviewed 2026-11-04