Claude can reject a WooCommerce orders or products result from a bridged tool with an error that begins “Structured content does not match the tool’s output schema”. The cause is a value that does not fit a format the source plugin declared, and Agent Abilities for MCP 1.8.1 stopped bridged tools from declaring those formats.
Takeaways:
- A strict client checks each value against the declared format, and one mismatch rejects the whole result.
- The fix takes two steps: update the plugin, then refresh Claude’s cached tool list.
- Input schemas, the plugin’s own
aafm/*tools and WordPress core’s validation were not touched.
How do I fix “does not match the tool’s output schema” in Claude?
Update Agent Abilities for MCP to 1.8.1 or later. Then, in Claude’s connector settings, use Refresh tools list (or reconnect the connector) so Claude forgets the old schema. Ask the question again.
What the error looks like
The report that led to this fix came from a wordpress.org support thread titled “Content does not match the tool’s output schema”. The user asked Claude to query WooCommerce orders through a bridged tool and got this:
Structured content does not match the tool's output schema:data/orders/0/date_created must match format "date-time"The failing tool was woocommerce/orders-query, and the page names four date fields on each order that did not fit the declared format. In that report, a query that returned no orders did not fail, which fits the cause below: with nothing to check, there is nothing to reject.
Why it happens
A bridged tool is one that another plugin registered, such as WooCommerce, and that this plugin serves through its own endpoint so the usual controls apply. Many of those tools publish an output schema, a description of the shape of their result. Under the MCP specification, a server that provides an output schema must return results that conform to it, and clients should validate results against it.
The schema had a format keyword on some fields, such as date-time. According to the JSON Schema documentation, format is only an annotation by default, and validators can optionally turn it into an assertion that fails the check. Claude is one of the strict clients that does. A date-time value follows RFC 3339, whose grammar requires a timezone, written as Z or an offset like +00:00.
WooCommerce returned order dates in the form 2026-10-15T10:00:00, with no timezone, and a product URL could be an empty string. Each value broke the format the schema promised, and the client threw away the whole result instead of one field.
The fix, in order
- Open the Dashboard tab and check the Versions card. You need 1.8.1 or later. The current release is 1.9.0.
- If you are behind, update the plugin from the Plugins screen.
- In Claude, open the connector’s settings and use Refresh tools list. Reconnecting the connector does the same job.
- Run the same question again.
The refresh matters. Claude keeps the schema from the last time it listed tools, so an updated plugin can still fail against the old copy.
What 1.8.1 changed
Changed: bridged tools no longer advertise any format keyword in their output schema.
Not changed:
- The values themselves. A date still arrives as WooCommerce sends it, and an empty URL is still empty.
- Input schemas.
- The plugin’s own
aafm/*abilities. - WordPress core’s validation.
No ability was added, removed or renamed, and no permission check moved. The release notes are on the changelog.
If it still fails
- Confirm the version again, then refresh the tools list a second time. Claude keeps the old schema until it refreshes, so rule that out first.
- Read the exact error. A different message means a different cause. The troubleshooting docs cover the other connection failures, and why ChatGPT or Claude can’t connect walks through the Connection Doctor.
- If the tool was never listed at all, see bridged tools now show up in the tool list.
Questions people ask
Does this affect only WooCommerce? The report was about WooCommerce orders and products. The change applies to every bridged tool, because none of them advertise strict formats any more.
Do I need to change anything in WooCommerce? No. The fix is in this plugin, and the values are unchanged.
Does the fix weaken the controls on bridged tools? No. Input schemas and permission checks are unchanged. This release only stops the tool from promising a format its values did not meet. How bridged tools are governed is in the safety controls docs.