[anzal1]

Closes #1045

What was added

Four new Client functions that return a cold Flow and follow nextCursor until the server returns none:

• toolsFlow(request, options): Flow<Tool>
• promptsFlow(request, options): Flow<Prompt>
• resourcesFlow(request, options): Flow<Resource>
• resourceTemplatesFlow(request, options): Flow<ResourceTemplate>

Behaviour:

• Cold: nothing is sent until the flow is collected, and each collection starts from the first page.
• Lazy: one page is requested at a time, as the collector consumes items. Cancelling the collector, take(n) or first() stops further requests, and a pending page request is cancelled with it.
• Errors from any page request (for example an McpException on page 2) are thrown to the collector after the earlier items were emitted.
• request is optional. If it carries a cursor, the flow starts there. Its _meta is sent with every page request. options apply to every page request.
• Pagination guard: if the server returns a nextCursor that was already used in this collection (including the starting cursor), the flow throws IllegalStateException instead of looping forever. The guard keeps a set of the cursors seen so far, so it also catches cycles longer than one page.

API

client.toolsFlow().collect { tool -> println(tool.name) }

val firstTen = client.toolsFlow().take(10).toList()

ABI change

This is an intentional API addition. updateKotlinAbi added 8 lines to kotlin-sdk-client/api/kotlin-sdk-client.api (the four functions and their $default synthetics) and 4 lines to kotlin-sdk-client.klib.api. No existing declaration changed.

Tests

ClientListFlowTest (commonTest, in-memory transport, backtick names) covers: multiple pages collected in order, a single page, an empty result, a cold flow that restarts per collection, cancellation mid-way (no further requests), take/first stopping early, cancelling an in-flight page request, an error on page 2 propagating, a repeated cursor, a cycle back to an earlier cursor, starting cursor and _meta handling, plus one ordering test each for prompts, resources and resource templates.

Run with JAVA_HOME=<JDK 21>:

./gradlew :kotlin-sdk-client:jvmTest --tests '*Flow*'
./gradlew :kotlin-sdk-client:jvmTest
./gradlew :kotlin-sdk-client:ktlintCheck :kotlin-sdk-client:detekt
./gradlew :kotlin-sdk-client:checkKotlinAbi   # fails before updateKotlinAbi, passes after
./gradlew :kotlin-sdk-client:updateKotlinAbi

I also checked the tests by mutation. With the cursor-follow broken, 10 of 14 tests fail. With the repeated-cursor guard removed, the two guard tests fail.

Only the client module JVM tests were run locally.

[jetbrains-air]

Nice work — the pagination helpers look solid, approving!

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