Recursively flatten nested lists into one flat list. Use it to simplify processing when items contain arbitrarily deep nested lists.
Recursively flatten nested lists.
Args: items: A potentially nested list to flatten.
| Name | Required | Description | Default |
|---|---|---|---|
| items | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v1.0.4Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full behavioral burden. 'Recursively' discloses that nesting is fully unwrapped, which is useful, but it omits everything else: how non-list scalars are handled, whether input order is preserved, and whether the input is mutated or a new list returned.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Front-loaded purpose followed by an args block; no wasted words. The Args formatting is slightly redundant for a single self-evident parameter, but the description remains tight.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
An output schema exists, so return values need not be explained. For a simple single-parameter utility the description covers the core operation, but with no annotations it leaves behavioral questions about mixed types and ordering unanswered.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0%, so the description must compensate. It adds the meaningful detail that the list may be nested (the schema merely says array of anything), but does not clarify acceptable element types or edge cases like deeply mixed nesting.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource ('Recursively flatten nested lists') with the adverb 'recursively' clarifying depth semantics. It is distinguishable from siblings like collection_merge or collection_chunk, though it does not explicitly contrast itself with them.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no guidance on when to use this tool versus alternatives such as collection_merge or collection_zip, nor any preconditions. Usage is only implied by the one-line purpose statement.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.