From 8328547c3d8dc20dcdf867f2208fa48c1f3238aa Mon Sep 17 00:00:00 2001
From: Matt Webb <matthew.webb@appfolio.com>
Date: Wed, 10 Jun 2026 17:58:07 -0700
Subject: [PATCH] Support Bedrock application inference profile ARNs as model
 ids
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Application inference profiles (used for cost-allocation tagging) are invoked by
passing their ARN as the modelId. The Bedrock provider built the request path as
"/model/#{@model.id}/converse" with the id raw, so an ARN's internal "/"
(".../application-inference-profile/<id>") was parsed as a path separator in both
the request URL and the SigV4 canonical path — AWS then rejected it with
"The provided model identifier is invalid".

Percent-encode the model id's "/" so the ARN stays a single path segment.
canonical_uri re-encodes per segment, which double-encodes it as SigV4 requires for
non-S3 services, keeping the signed and sent paths consistent. No-op for ordinary
model ids (which contain no "/"); ":" version suffixes are valid path-segment
characters and are unaffected.
---
 lib/ruby_llm/protocols/converse/chat.rb      |  8 ++++-
 lib/ruby_llm/protocols/converse/streaming.rb |  2 +-
 spec/ruby_llm/providers/bedrock_spec.rb      | 38 ++++++++++++++++++++
 3 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/lib/ruby_llm/protocols/converse/chat.rb b/lib/ruby_llm/protocols/converse/chat.rb
index 38a9c9b5c..cb2545437 100644
--- a/lib/ruby_llm/protocols/converse/chat.rb
+++ b/lib/ruby_llm/protocols/converse/chat.rb
@@ -13,7 +13,13 @@ module Chat
         module_function
 
         def completion_url
-          "/model/#{@model.id}/converse"
+          "/model/#{escape_model_id(@model.id)}/converse"
+        end
+
+        # Application inference profile ARNs contain '/', but Bedrock expects the model id
+        # to remain one path segment.
+        def escape_model_id(model_id)
+          model_id.to_s.gsub('/', '%2F')
         end
 
         # rubocop:disable Metrics/ParameterLists,Lint/UnusedMethodArgument
diff --git a/lib/ruby_llm/protocols/converse/streaming.rb b/lib/ruby_llm/protocols/converse/streaming.rb
index 56168c955..c54c5e990 100644
--- a/lib/ruby_llm/protocols/converse/streaming.rb
+++ b/lib/ruby_llm/protocols/converse/streaming.rb
@@ -14,7 +14,7 @@ module Streaming
         private
 
         def stream_url
-          "/model/#{@model.id}/converse-stream"
+          "/model/#{escape_model_id(@model.id)}/converse-stream"
         end
 
         def stream_response(payload, additional_headers = {}, &block)
diff --git a/spec/ruby_llm/providers/bedrock_spec.rb b/spec/ruby_llm/providers/bedrock_spec.rb
index 995d26f26..91c45378b 100644
--- a/spec/ruby_llm/providers/bedrock_spec.rb
+++ b/spec/ruby_llm/providers/bedrock_spec.rb
@@ -160,4 +160,42 @@ def credential_provider(credentials = self.credentials)
       expect(provider.protocol_for(model)).to eq(RubyLLM::Protocols::Converse)
     end
   end
+
+  describe 'model id path encoding' do
+    let(:converse) { RubyLLM::Protocols::Converse.allocate }
+    let(:arn) { 'arn:aws:bedrock:us-west-2:123:application-inference-profile/p' }
+
+    def with_model(id)
+      converse.instance_variable_set(:@model, instance_double(RubyLLM::Model, id: id))
+    end
+
+    it 'keeps an application inference profile ARN as a single path segment in the converse URL' do
+      with_model(arn)
+      expect(converse.send(:completion_url)).to eq(
+        '/model/arn:aws:bedrock:us-west-2:123:application-inference-profile%2Fp/converse'
+      )
+    end
+
+    it 'encodes the ARN for the converse-stream URL too' do
+      with_model(arn)
+      expect(converse.send(:stream_url)).to eq(
+        '/model/arn:aws:bedrock:us-west-2:123:application-inference-profile%2Fp/converse-stream'
+      )
+    end
+
+    it 'leaves ordinary model ids (including a ":" version suffix) unchanged' do
+      with_model('us.anthropic.claude-sonnet-4-5-20250929-v1:0')
+      expect(converse.send(:completion_url)).to eq(
+        '/model/us.anthropic.claude-sonnet-4-5-20250929-v1:0/converse'
+      )
+    end
+
+    it 'signs the ARN as one segment (SigV4 canonical path double-encodes "/", not truncates)' do
+      with_model(arn)
+      path = URI.parse(converse.send(:completion_url)).path
+      expect(described_class.allocate.send(:canonical_uri, path)).to eq(
+        '/model/arn%3Aaws%3Abedrock%3Aus-west-2%3A123%3Aapplication-inference-profile%252Fp/converse'
+      )
+    end
+  end
 end