MCP Datastore Server

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions creating keys but doesn't specify if this is a read-only operation, has side effects (e.g., persists data), requires authentication, or involves rate limits. The term 'create' suggests a mutation, but without annotations, critical behavioral traits like safety or idempotency are missing, making it inadequate for informed tool selection.

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?

The description is a single, efficient sentence that front-loads the core action. It avoids redundancy and wastes no words, though it could be more informative. However, its brevity borders on under-specification, as it lacks explanatory depth, slightly reducing its effectiveness despite good structure.

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?

Given the complexity of a key creation tool with 4 parameters, no annotations, and no output schema, the description is incomplete. It doesn't explain the return value (e.g., the created key object), error conditions, or how it integrates with sibling tools like datastore_insert. For a mutation tool in a datastore context, more context is needed to ensure proper usage, making this insufficient.

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%, so the schema fully documents all parameters (kind, keyId, namespace, path). The description adds minimal value by hinting at 'complete' vs. 'incomplete' keys, which loosely maps to optional keyId, but doesn't explain the semantics beyond what the schema provides (e.g., what makes a key 'complete'). This meets the baseline for high schema coverage without significant enhancement.

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?

The description states the action ('Create') and resource ('key'), but it's vague about what a 'key' is in this context (e.g., a database key, identifier, or cryptographic key). It distinguishes between 'complete' and 'incomplete' keys, but without explaining the difference or purpose, leaving the agent to infer from parameters. This is better than a tautology but lacks specificity compared to siblings like datastore_insert or datastore_get.

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 guidance is provided on when to use this tool versus alternatives. For example, it doesn't explain if this is for generating keys before insertion (datastore_insert) or for other purposes, nor does it mention prerequisites like existing data. The description implies usage through the 'complete/incomplete' distinction but doesn't clarify when each is appropriate, leaving the agent to guess based on parameters alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.