MATLAB output in Claude Code shows raw HTML for hyperlinks

[michellehirsch]

The output displayed in Claude Code shows hyperlinks, which can make the output extremely difficult to read. Can we disable hotlinks (feature("hotlinks",false)) when launching or connecting to a MATLAB session?

Here's an example that shows how bad it can be:

 matlab - evaluate_matlab_code (MCP)(project_path: "/Users/michellehirsch/Coding/Agent Experiments/MATLAB/Claude/toml", code:
                                     "buildtool test")
  ⎿  Error: matlab error: arseKeyValue</a> (<a href="matlab: opentoline('/Users/michellehirsch/Coding/Agent 
     Experiments/MATLAB/Claude/toml/toolbox/readtoml.m',245,0)">line 245</a>)
                 trackKeyOrder(metadata, tablePath, key);
         
         Error in <a href="matlab:matlab.lang.internal.introspective.errorDocCallback('readtoml>parseToml', 
     '/Users/michellehirsch/Coding/Agent Experiments/MATLAB/Claude/toml/toolbox/readtoml.m', 89)" 
     style="font-weight:bold">readtoml>parseToml</a> (<a href="matlab: opentoline('/Users/michellehirsch/Coding/Agent 
     Experiments/MATLAB/Claude/toml/toolbox/readtoml.m',89,0)">line 89</a>)
                     [data, currentTable] = parseKeyValue(data, currentTable, currentTablePath, line, datetimeType, metadata);
         
         Error in <a href="matlab:matlab.lang.internal.introspective.errorDocCallback('readtoml', 
     '/Users/michellehirsch/Coding/Agent Experiments/MATLAB/Claude/toml/toolbox/readtoml.m', 32)" 
     style="font-weight:bold">readtoml</a> (<a href="matlab: opentoline('/Users/michellehirsch/Coding/Agent 
     Experiments/MATLAB/Claude/toml/toolbox/readtoml.m',32,0)">line 32</a>)
             [data, metadata] = parseToml(fileContent, options.DatetimeType);
         
         Error in <a href="matlab:matlab.lang.internal.introspective.errorDocCallback('toml_test/testInlineTable', 
     '/Users/michellehirsch/Coding/Agent Experiments/MATLAB/Claude/toml/tests/toml_test.m', 143)" 
     style="font-weight:bold">toml_test/testInlineTable</a> (<a href="matlab: opentoline('/Users/michellehirsch/Coding/Agent 
     Experiments/MATLAB/Claude/toml/tests/toml_test.m',143,0)">line 143</a>)
     … +110 lines (ctrl+o to see all)

[wuych1]

Similar thing for help <function> syntax. Not sure if this should be a separate issue. But those href links really overwhelm the content and seriously bloat the context without having enough information.

[agoldsbo]

Thank you for bringing this to our attention. We will consider it as we evolve our roadmap.

[nightfury1802]

This is part of a broader output verbosity problem — the HTML links are just the most visible symptom. Error messages from MATLAB include <a href="matlab:opentoline(...)">function (line N)</a> wrappers on every stack frame, and when you have a deep call stack (5–10 frames) or repeated warnings (one per solver step), the context fill-up is significant.

Two things that help today:

1. MATLAB-level fix — feature("hotlinks", false) disables hyperlink generation. You can inject this at session start via --run-matlab-on-startup or the equivalent. The MCP server could consider calling this automatically.

2. Proxy-level fix — I built a transparent stdio proxy that sits between Claude Code and matlab-mcp-core-server and applies domain-specific compression rules to tool responses. Among other things it:

• Collapses deep stack traces to first frame + entry point (removing the hyperlink-heavy middle frames)
• Deduplicates repeated warnings (the worst offenders for context fill)
• Strips Simscape error boilerplate that always precedes the useful message

Overall 48–66% token reduction on Simscape simulation output: https://github.com/nightfury1802/matlab-mcp-proxy

Stripping the <a href="..."> HTML tags themselves would be a clean addition — would work well as a pre-processing step before the rest of the compression pipeline.