sync_schemas.py: support ADCP_BASE_URL env override for parity with JS SDK

[bokelley]

Context

DX-expert pre-merge review of #275 flagged a parity gap with the JS SDK:

• @adcp/client/scripts/sync-schemas.ts reads ADCP_BASE_URL from env (defaults to https://adcontextprotocol.org), so CI / local dev can point sync at a fake CDN serving a fixture tarball.
• adcp-client-python/scripts/sync_schemas.py hardcodes BUNDLE_BASE_URL = "https://adcontextprotocol.org/protocol" as a module constant. No way to redirect without editing source.

This bites whenever someone wants to:

• Run cross-SDK CI against a fixture server (e.g. validate that JS + Python sync produce equivalent local trees from the same tarball).
• Test sync_schemas.py locally against a release tarball that hasn't deployed to production yet.
• Stand up an integration test that exercises the full sync pipeline without depending on the live CDN.

Proposal

Match the JS pattern: BUNDLE_BASE_URL = os.environ.get("ADCP_BASE_URL", "https://adcontextprotocol.org") + "/protocol".

Same env var name (ADCP_BASE_URL) so cross-SDK CI scripts can set it once.

Out of scope

• Other configuration drift between the two SDKs (separate triage)
• Adding integration tests that exercise the env override (would be nice, not required)

References

• JS implementation: @adcp/client scripts/sync-schemas.ts:23 (search for ADCP_BASE_URL)
• Python implementation today: scripts/sync_schemas.py BUNDLE_BASE_URL constant
• Surfaced by dx-expert review of feat(adcp): sync canonical agent skills from protocol tarball #275

[bokelley]

Triage

Classification: Feature request
Bucket(s): no label match — scripts/ tooling DX has no defined label; gap flagged in run summary
Status: drafting-pr
Milestone: (omitted)

What the experts said:

• code-reviewer: approved after fixing env-sensitive test_default_value (relied on already-loaded _mod; switched to fresh module load + monkeypatch.delenv)
• dx-expert: approved — .rstrip("/") guard addresses the trailing-slash / doubled /protocol edge case; ! sigil convention followed; JS SDK parity confirmed

My take: Minimal non-breaking change — default behavior is identical, the env var adds a zero-config redirect for fixture-CDN CI. PR #285 drafts the fix with three new tests covering the default, override, and trailing-slash cases.

Drafted PR: #285 — feat(adcp): support ADCP_BASE_URL env override in sync_schemas.py

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Triaged by Claude Code. Session: https://claude.ai/code/session_01KXfYPHYKr3R6EDqUbbo9ty

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Generated by Claude Code