feat(fetch): add tool annotations#3643
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owendevereaux wants to merge 1 commit intomodelcontextprotocol:mainfrom
Open
feat(fetch): add tool annotations#3643owendevereaux wants to merge 1 commit intomodelcontextprotocol:mainfrom
owendevereaux wants to merge 1 commit intomodelcontextprotocol:mainfrom
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…nt, openWorld hints Adds ToolAnnotations to the fetch tool: - readOnlyHint: true (GET requests only, no modifications) - destructiveHint: false (read-only operation) - idempotentHint: true (same URL returns same content) - openWorldHint: true (makes outbound HTTP requests to arbitrary URLs) The openWorldHint is particularly important as fetch can reach any URL, making it a key consideration for clients enforcing data exfiltration policies. Closes modelcontextprotocol#3572
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Summary
Adds tool annotations to the fetch server's single tool, implementing the request in #3572.
Changes
Added
ToolAnnotationsto thefetchtool with:readOnlyHinttruedestructiveHintfalseidempotentHinttrueopenWorldHinttrueThe
openWorldHint: trueis particularly important — the fetch tool can reach any URL on the internet, making it a key vector for data exfiltration in multi-server setups. Accurate annotations help clients enforce "allow reads, gate sends" policies.Testing
python -m py_compileToolAnnotationsCloses #3572