kg_at

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

Annotations already declare readOnlyHint and idempotentHint, so safety is covered. The description adds the key behavioral nuance of timestamp filtering, which is useful. However, it does not describe the return format, potential limits, or error conditions. Given that annotations cover the safety aspects, this is adequate but not exceptional.

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 two sentences with no redundant words. It directly states the purpose and the optional behavior of the timestamp parameter. Every word serves a purpose, making it highly concise and well-structured.

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 query tool in a knowledge graph context, the description sufficiently explains how to use it: specify a timestamp for point-in-time valid facts, or omit for current ones. It distinguishes itself from timeline tools by focusing on a single time point. The unmentioned parameters are standard in such domains (subject, predicate, object) and likely understandable. A small deduction for not specifying the output shape, but overall it is complete enough for an agent to call correctly.

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?

Only the timestamp parameter is described in the schema and referenced in the description. The other five parameters (limit, object, project, subject, predicate) have no descriptions and are not mentioned. With schema coverage at only 17%, the description fails to compensate for the missing parameter documentation, leaving most of the parameters underspecified.

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 tool returns fact assertions valid at a specific timestamp, or current facts if timestamp is omitted. This makes the core purpose unambiguous without needing to inspect the schema. However, it does not explicitly distinguish itself from sibling tools like kg_timeline, so it loses a point.

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 a clear condition for usage: include timestamp for point-in-time queries, omit for current facts. This gives practical guidance, but it does not mention when to prefer this over other query tools or mention any limitations (e.g., pagination, ordering). The guidance is implicit rather than explicit.

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