Read the metadata associated with a key in a Workers KV namespace.
Read the metadata associated with a key in a Workers KV namespace.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes | required,The key whose metadata to read | |
| account_id | Yes | required,The ID of the Cloudflare account | |
| namespace_id | Yes | required,The ID of the KV namespace |
Changes observed during successful MCP inspections.
v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. The verb 'Read' does convey a non-mutating operation, which is useful, but nothing is said about required permissions, behavior when the key or metadata does not exist, or rate limits.
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?
A single front-loaded sentence with zero filler. The verb and resource lead immediately, and nothing is redundant.
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?
Adequate for a simple read with fully documented parameters and no output schema. However, it omits when to prefer this over get_kv_value and gives no sense of what the returned metadata contains, leaving minor gaps for an agent.
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% and all three parameters (account_id, namespace_id, key) are self-explanatory and individually documented. The description adds no format, ID, or lookup semantics beyond the schema, so the baseline of 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?
States a specific verb and resource: read metadata for a key in a Workers KV namespace. The word 'metadata' implicitly separates it from get_kv_value and get_kv_pairs_bulk, but no sibling is named explicitly, so differentiation relies on the agent's inference.
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?
No when-to-use guidance and no alternatives named. With siblings like get_kv_value, get_kv_namespace, and list_kv_keys present, an explicit statement such as 'use this instead of get_kv_value when you only need metadata' would have been valuable and is absent.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.