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 reveals that the tool returns first/last decode dates, decode_count, and dated change entries, and clarifies that an empty history means 'measured, stable so far' rather than an error. It also describes the token-level diff format with examples, giving strong insight into expected output behavior.

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 front-loaded with the core purpose, uses examples to illustrate the diff format efficiently, and includes a concise parameter definition and return value summary. Every sentence adds useful information without redundancy.

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 single parameter and no output schema, the description provides a complete picture: it explains the input format, what the output contains, and even the interpretation of an empty result. It leaves no significant gaps for the agent to guess.

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?

The schema only names the parameter 'site' with no description. The tool description compensates fully by defining site as 'a domain ("stripe.com") or product name' with a concrete example. This is the only parameter, and its semantics are made clear.

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 identifies the tool as returning measured design CHANGE HISTORY for a live-decoded domain, with concrete examples of token-level diffs. It distinguishes itself from screenshot-based tools by emphasizing historical evolution, which separates it from sibling tools like get_design_system or get_screen.

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?

It explicitly states the intended use: 'Use it to see how a product's design system is EVOLVING.' It also notes that screenshots cannot backfill this data, providing contrast. However, it does not name specific sibling tools as alternatives or explicitly state when not to use it.

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