replay_diff

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

Annotations indicate readOnlyHint=true, so the read-only nature is covered. Description adds requirements and return format, but no additional behavioral traits (e.g., no mention of pagination, limits, or side effects). With annotations, 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?

Very concise: 4 sentences total, front-loaded with purpose, followed by requirements and parameter details. No 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?

For a simple diff tool with readOnlyHint and output schema available, the description covers purpose, parameters, and return type. Could mention example output structure or limits, but overall complete enough.

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 coverage is 0%, so description carries full burden. It explicitly documents both parameters ('start: Start timestamp (ISO)', 'end: End timestamp (ISO)'), adding type and format meaning beyond the bare schema.

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?

Description clearly states it diffs memory state between timestamps, showing added/removed/modified. Distinguishes from siblings like draft_diff by focusing on memory state over time, though not explicitly contrasting.

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?

Mentions a prerequisite (Pro tier or Novyx Cloud) but provides no guidance on when to use this vs alternatives like replay_memory, draft_diff, or replay_timeline. Lacks when-not-to-use context.

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