Architecture
Timebound IAM runs as an MCP (Model Context Protocol) server that your AI agent communicates with through standard tool calls. Instead of giving your agent long-lived AWS keys, the agent requests exactly the permissions it needs, for a short period of time.
The server uses AWS STS AssumeRole to generate temporary credentials scoped to specific services. Session policies are built from standard AWS managed policy actions -- the same actions AWS already defines for each service -- so you're not relying on custom or hand-rolled permission sets. These credentials are written to a secure file on disk -- never passed through the chat context -- and are automatically cleaned up when they expire.
Credential Flow
Agent requests access
The agent calls grant_access specifying the services, access level, and TTL it needs.
Handler validates the request
The MCP handler checks services are supported, TTL is within bounds (15m-12h), and the requested level is valid.
STS AssumeRole
The server calls AWS STS to assume the timebound-iam-broker role with a session policy scoped to only the requested services.
Credentials written to secure file
Temporary credentials are written to a profile-specific file with 0600 permissions. The file path is returned to the agent.
Auto-cleanup on expiry
When the TTL expires, credentials are automatically removed from disk. The agent can request new credentials at any time.
Security Properties
Every design decision prioritizes minimizing the blast radius of credential exposure.
Time-bounded
Credentials expire automatically. No permanent access is ever granted.
Service-scoped
Session policies restrict access to only the specific AWS services requested.
File-based
Credentials are written to disk with 0600 permissions, never passed through the chat context.
Scoped permissions
Session policies use standard AWS managed policy actions to scope access to only the requested services.
Per-profile isolation
Each AWS profile gets its own credential file and IAM role, preventing cross-account leakage.
Auto-cleanup
Expired credentials are removed from disk. No stale secrets accumulate over time.