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

With no annotations provided, the description carries the full burden. It discloses that the operation is read-only and free, values are redacted unless include_values is set, and overly large diffs are refused rather than silently truncated. This gives the agent important behavioral expectations.

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 concise, with the main purpose in the first line and additional key behaviors following. Every sentence adds value, and it is not padded with fluff.

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?

The description covers essential behavioral context: read-only, free, redaction behavior, and refusal of large diffs. The output schema exists, so return format need not be detailed. However, it does not mention the limit parameter or edge cases, which would make it fully complete.

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 0%, so the description must compensate. It explains the semantics of to_snapshot_id (optional, defaults to current state) and include_values (controls value redaction), but does not explain limit or from_snapshot_id in detail. This partial coverage earns a 3.

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 primary action: 'Compare a checkpoint against another checkpoint or current state.' This uses a specific verb ('Compare') and resource ('checkpoint'), and the mention of 'current state' distinguishes it from sibling tools like snapshot or rollback.

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?

Provides clear context for when to use the tool: to compare checkpoints or see changes since a checkpoint. It also explains the key behavior of leaving to_snapshot_id empty. However, it does not explicitly mention alternatives or when not to use it, which keeps it from a 5.

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