list_named_shadowsList named AWS IoT device shadows for a specific thing to inspect per-shadow state; the classic unnamed shadow is excluded.
Lists the named shadows that exist for one thing. The classic (unnamed) shadow is never listed here by AWS — read it with get_device_shadow and no shadow_name.
| Name | Required | Description | Default |
|---|---|---|---|
| thing_name | Yes | Exact AWS IoT thing name. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds a genuinely non-obvious AWS behavior: the classic shadow is excluded from results. It does not mention pagination or result ordering, which would be the remaining behavioral gap.
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 tight sentences with zero filler. The primary behavior is front-loaded and the exclusion/alternative follows immediately.
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?
With no output schema, the description leaves the return shape (a list of shadow names) and pagination unspecified. However, annotations carry the safety profile and the key semantic trap (classic shadow exclusion) is fully covered, so the definition is nearly complete for a simple one-parameter list tool.
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 100% for the single required parameter, so the schema already carries the meaning ('Exact AWS IoT thing name'). The description adds no format or constraint detail beyond it; baseline 3 applies.
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?
Specific verb ('Lists') plus resource ('named shadows') plus scope ('that exist for one thing'). It immediately distinguishes itself from get_device_shadow by explicitly scoping to named shadows only.
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?
Explicitly states when this tool does NOT apply (the classic unnamed shadow is never listed) and names the alternative tool and invocation pattern (get_device_shadow with no shadow_name). This is exactly the routing guidance an agent needs given get_device_shadow is a sibling.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.