lambda_create_filesystemCreate a new persistent filesystem in a region (can then be attached to instances at launch). Lambda Cloud REST: POST /api/v1/filesystems.
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | Filesystem name (1-60 chars, must start with a letter, then letters/digits/hyphens — pattern ^[a-zA-Z]+[0-9a-zA-Z-]*$). | |
| region | Yes | Region to create the filesystem in (e.g. 'us-east-1'). |
Changes observed during successful MCP inspections.
Input schema / $schemaPrevious value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, so the description needn't restate the safety profile. It adds the useful behavioral fact that the filesystem is 'persistent' and confirms the underlying REST operation (POST /api/v1/filesystems), but says nothing about permissions, quotas, or whether region is immutable after creation.
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?
Two short sentences, zero waste, with the primary action and scope front-loaded before the lifecycle note and endpoint. Nothing to trim.
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?
For a simple two-parameter creation tool with full schema coverage and no output schema, the description covers purpose, scope, and follow-on use. It stops short of stating the creation result (e.g. an ID to reuse) or any regional constraints, which are minor gaps at this complexity.
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 coverage is 100% and both parameters carry pattern/format details (name regex, region example), so the schema does the heavy lifting. The description adds no parameter-level meaning beyond naming the region concept, which is the baseline-3 case.
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+resource ('Create a new persistent filesystem') with scope ('in a region') and adds what happens next ('can then be attached to instances at launch'). An agent can tell this apart from lambda_delete_filesystem and lambda_list_filesystems without inspecting the schema.
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?
The workflow hint that the filesystem 'can then be attached to instances at launch' implies when this tool fits in a sequence, but there is no explicit when-to-use/when-not guidance or named alternative. Usage is inferred rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.