agent_browser_code strict schema breaks every request on Anthropic strict-tool models (minimum/maximum not supported)

[vruru]

Summary

With pi 0.87.1 and a model that supports strict tools (anthropic/claude-opus-5-5), every request fails once pi-agent-browser-native@0.7.1 is loaded:

400 {"type":"error","error":{"type":"invalid_request_error","message":"tools.25.custom: For 'integer' type, properties maximum, minimum are not supported"}}

agent_browser_code registers constrainedSampling: { type: "json_schema", strict: "prefer" }, and createAgentBrowserCodeParamsSchema() contains keywords Anthropic strict mode doesn't accept:

• timeoutMs: Type.Integer({ minimum: 1, maximum: AGENT_BROWSER_CODE_MAX_TIMEOUT_MS })
• code: Type.String({ minLength: 1, maxLength: 65_536 }), session: Type.String({ minLength: 1 })

Pi's strict conversion currently passes them through unchanged (reported upstream: earendil-works/pi#9953), so the whole session breaks, not just this tool.

Suggested fix

Until pi sanitizes this, either drop constrainedSampling from agent_browser_code, or keep it but move the bounds into descriptions and enforce them in execute (the runtime check is needed anyway).

Local workaround confirmed: commenting out the constrainedSampling line in dist/extensions/agent-browser/lib/tool-surface.js makes the schema error go away.

[jetnet]

Also reproduces on 0.7.0, so the update alone won't clear it: that build has no lib/tool-surface.js, the bounds live in lib/input-modes/params.js:34 (timeoutMs: Type.Optional(Type.Integer({ minimum: 1, maximum: 300000 }))), and with pi 0.87.1 every request on a strict-tool model fails — saw it on both anthropic/claude-opus-4-8 and anthropic/claude-opus-5:

tools.14.custom: For 'integer' type, properties maximum, minimum are not supported

One correction to the diagnosis: the string bounds are fine. Removing only the numeric keys (minimum/maximum, including inside the anyOf null-union that makeStrictJsonSchema() builds for optional fields) is enough — the same request then returns 200 with code: { minLength, maxLength } untouched.

Workaround in use: a before_provider_request handler that drops numeric bound keywords from Anthropic input_schema trees. Covers strict tools from every source, MCP schemas included.