Requirements, architecture and delivery for a Ministry of Interior engagement with government security constraints.
Multiple agencies, legacy systems that could not change, and a security posture that ruled out most of the easy answers. The risk was not the code — it was building the wrong thing carefully.
Wrote the SRS and SDD as decision records: interfaces with failure modes named, security controls mapped to the requirement that demanded them.
Proved the integration layer with a proof of concept before the plan was signed.
Sequenced delivery so "phase two" meant something.
Signed off and deployed to production. The specification is still the document the teams argue from.