[Travis Angevine (trangevi)]

Why

Toolbox deployment can run before an agent's predeploy hook grants the developer Foundry data-plane access. Subscription Owner or Contributor alone is not sufficient, and standalone toolbox writes never reach that hook.

Fixes: #10718

Approach

• Prepare access before managed toolbox deployment and standalone write operations, after local validation but before remote connection resolution or mutation.
• Share access policy and environment, project-scope, tenant, and credential helpers through core pkg/foundry, used by both agents and toolboxes. Keep only service-specific probes and output/error mapping in the extensions.
• Probe effective access first, preserving custom or externally managed permissions without requiring role-assignment writes. On a confirmed authorization denial, inspect inherited roles, conditionally assign project-scoped Foundry User, and wait for bounded propagation.
• Use user-access tenant credentials and resource-tenant principal resolution for guest users and service principals. Unrelated explicit endpoints never borrow the active environment's project scope or tenant.
• Preserve opt-out precedence, hosted-agent permission checks, and stderr warnings for toolbox JSON output. Provisioning, read/delete operations, local authoring, and bring-your-own endpoint publication do not automatically grant developer roles.

Release sequencing

This draft includes both the core helpers and extension consumers for review. The new core SDK APIs must land and be released first, then the independently published extensions must update their SDK dependencies. Their current v1.37.0 pins do not include these APIs; cross-module validation used an external Go workspace, with no repository-local replacements.

Validation

• Core Foundry tests, including an independent module run.
• Full toolbox tests, agents project tests, and agents command short suite.
• Both extension builds, targeted vet, lint, Go modernization, spelling, and diff checks.
• Updated and statically validated the Tier 2 2.00-setup-deploy-shared-agent.yaml scenario. No live Azure scenario was run; live verification requires the foundry-extension-scenario-orchestrator and incurs Azure cost.

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[Travis Angevine (trangevi)]

Superseded by the requested three-PR draft stack: #10738 (core Foundry helpers), #10739 (targeted toolbox deploy/create fix for #10718), and #10740 (broader write coverage and agent consolidation). Native stack #10741 preserves that bottom-to-top order. The replacement layers include injected access-propagation feedback and retain the probe-first, endpoint-bound access policy. Core release and real extension SDK dependency bumps remain required before publishing consumers. Original branch retained for reference.