MCP Datastore Server

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

With no annotations provided, the description carries full burden but only states it 'gets' an entity without disclosing behavioral traits. It doesn't cover error handling (e.g., if the entity doesn't exist), permissions required, rate limits, or what the return format looks like (since there's no output schema). This is inadequate for a tool with mutation siblings like delete/update.

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 directly states the tool's function without unnecessary words. It's front-loaded with the core action and resource, making it easy to parse quickly.

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 Datastore operations and the lack of annotations and output schema, the description is incomplete. It doesn't explain what 'Get' entails operationally (e.g., is it a direct lookup?), how results are returned, or error cases, leaving gaps for the agent to infer behavior in a context with mutation tools.

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 parameters are well-documented in the schema. The description adds no additional meaning beyond implying the tool uses 'kind and key' (matching the required parameters). This meets the baseline for high schema coverage but doesn't enhance understanding.

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 clearly states the action ('Get') and resource ('an entity by kind and key from Datastore'), making the purpose understandable. However, it doesn't explicitly differentiate this read operation from sibling tools like datastore_query or datastore_listKinds, which also retrieve data but with different approaches.

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 description provides no guidance on when to use this tool versus alternatives. It doesn't mention scenarios like retrieving a single known entity (vs. datastore_query for filtered searches) or prerequisites such as needing the exact key. This leaves the agent without context for tool selection.

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