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 only says that snapshots are 'from Wayback Machine', which suggests an external lookup but does not explain what the query parameter 'q' does, what the output looks like, whether results are limited to one snapshot or many, or any constraints such as rate limits or date filters. This is minimal behavioral context, far below what is needed given zero annotation support.

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 short noun phrase that largely restates the tool name and title, adding only 'from Wayback Machine'. It is under-specified rather than appropriately concise: the one sentence does not earn its place because it omits essential information about the parameter and behavior, while repeating what is already in the title.

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?

Although the tool is simple (one optional parameter, no required fields), the description is incomplete. It provides no explanation of the input parameter, no output expectations, and no usage context. The presence of an output schema helps, but without viewing it or having any description of its contents, the agent lacks enough information to correctly select and invoke this tool.

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% and the single parameter 'q' has no description in the schema. The tool description does not mention 'q' at all, let alone clarify whether it expects a domain, URL, or other identifier. With the schema providing no semantics and the description adding none, the agent cannot determine what value to pass to the parameter.

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 states that the tool provides 'Historical robots.txt snapshots from Wayback Machine', which clearly identifies the resource (robots.txt history) and the source (Wayback Machine). It is not a tautology because it adds the Wayback Machine detail beyond the tool name, and it implicitly distinguishes from siblings like 'robots' (current robots.txt) and 'robotsmeta'. However, it lacks an explicit verb (fetch/retrieve) and does not directly differentiate from broader siblings like 'wayback' or 'cdxwayback'.

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 gives no guidance on when to use this tool versus alternatives such as 'wayback', 'cdxwayback', 'robots', or 'robotsmeta'. There is no mention of the intended use case, query context, or any exclusions. The absence of any usage direction leaves the agent without criteria for selecting this tool over closely related siblings.

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