fix: handle non-array MCP tool result.content to prevent TypeError

[usvimal]

Summary

Fixes TypeError: {} is not iterable error when MCP tools (like Claude's built-in discard and extract context management tools) return results with non-array content values.

Problem

In packages/opencode/src/session/prompt.ts:770, the code iterates over result.content assuming it's always an array:

for (const contentItem of result.content) {

When an MCP tool returns content as undefined, {}, or any non-array value, this throws:

TypeError: {} is not iterable

Solution

Added an Array.isArray() guard to safely handle non-array content:

const contentArray = Array.isArray(result.content) ? result.content : []
for (const contentItem of contentArray) {

Testing

Reproduced the error using Claude's built-in discard and extract tools, verified the fix prevents the error while maintaining correct behavior for standard MCP tool results.

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