Add McpAdapter::on_init() helper for safe server registration#217
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arunshenoy99 wants to merge 2 commits into
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Add McpAdapter::on_init() helper for safe server registration#217arunshenoy99 wants to merge 2 commits into
arunshenoy99 wants to merge 2 commits into
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The mcp_adapter_init action name is global, so when more than one copy of this library is active in the same request (e.g. two plugins that each vendor wordpress/mcp-adapter, with or without namespace prefixing), every copy's dispatch runs every copy's subscribers. A subscriber that registers servers without checking which adapter dispatched causes duplicate registration errors on subsequent dispatches. on_init() wraps add_action( 'mcp_adapter_init', ... ) with an identity check so the callback only runs when this adapter is the one dispatching. Consumers that already use the $adapter passed to their mcp_adapter_init callback are equally safe; this helper just makes that guarantee explicit. Adds two unit tests (matching and foreign adapter) and a README section documenting the helper alongside the existing custom-server example.
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Reframe the on_init() docblock from "prefer this over add_action()" to "an alternative to add_action() that builds the identity guard in", and make explicit that a subscriber using the $adapter passed to its mcp_adapter_init callback is already safe. The helper is an ergonomic convenience, not a required replacement for the action.
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Summary
Adds
McpAdapter::on_init(), a small convenience wrapper aroundadd_action( 'mcp_adapter_init', ... )that builds an adapter-identity check in for the caller.This was split out of #173 (per review feedback) so the new public API can be discussed and documented on its own. The
duplicate_server_idcrash itself is fixed independently by the factory guard in #173; this helper is an ergonomic addition, not required for that fix.Why
The
mcp_adapter_initaction name is global. When more than one active plugin vendorswordpress/mcp-adapter(with or without namespace prefixing), every copy's dispatch runs every copy's subscribers. A subscriber that registers servers without checking which adapter dispatched ends up registering on every dispatch, causing duplicate-registration errors.A consumer that uses the
$adapterpassed to itsmcp_adapter_initcallback is already safe.on_init()simply makes that guarantee explicit and harder to get wrong:The wrapped callback only runs when this adapter is the one dispatching.
Public API note
This adds a new public method, so it is a commitment once shipped — hence the dedicated PR and docs. Feedback on the name/shape welcome.
Tests & docs
$adapteroverMcpAdapter::instance()insidemcp_adapter_initcallbacks.