fix(client/auth): use .set() for prompt=consent instead of .append() to avoid duplicating#1958
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mhegazy wants to merge 2 commits intomodelcontextprotocol:mainfrom
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fix(client/auth): use .set() for prompt=consent instead of .append() to avoid duplicating#1958mhegazy wants to merge 2 commits intomodelcontextprotocol:mainfrom
mhegazy wants to merge 2 commits intomodelcontextprotocol:mainfrom
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… duplicating When the AS metadata's authorization_endpoint already includes a prompt query parameter (permitted by RFC 6749 §3.1, which says clients MUST retain it), startAuthorization's offline_access handling appended a second prompt=consent. RFC 6749 §3.1 also states parameters MUST NOT be included more than once; Azure AD enforces this and rejects the request with AADSTS9000411. OIDC Core §3.1.2.1 defines prompt as a space-delimited list, so merge consent into the existing value as a single parameter. Ref: anthropics/claude-code#31089
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@modelcontextprotocol/express
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mhegazy
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Problem
When the authorization server's
authorization_endpointmetadata already includes apromptquery parameter,startAuthorizationappends a secondprompt=consent(when scope containsoffline_access), producing a request with twopromptparameters. Azure AD rejects this withAADSTS9000411: The parameter 'prompt' is duplicated.Real-world example: Anthropic's hosted Microsoft 365 MCP server publishes
authorization_endpoint: "https://login.microsoftonline.com/.../authorize?prompt=select_account". The resulting URL contains bothprompt=select_accountandprompt=consent.Spec
promptas space-delimited, but Azure AD rejects that form too (AADSTS90023: Unsupported 'prompt' value) — it only accepts a single value.offline_accessis requested,prompt=consentMUST be used. Soconsentis the value that needs to win.Fix
.append()→.set(). If the endpoint already carries apromptvalue,consentoverwrites it — this is the only portable choice given Azure's single-value constraint, andconsentis the value OIDC §11 mandates for theoffline_accessflow this branch guards.References