Check Performance Budget

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

Annotations declare readOnlyHint: true and openWorldHint: true, indicating a read-only operation that may access external resources. The description adds no extra behavioral context—it does not mention that the tool will perform a live audit, make network requests, or have rate limits. While there is no contradiction, the description fails to disclose the operation's networked nature, which is a meaningful behavioral trait beyond the annotations.

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, efficient sentence with no filler. It conveys the purpose immediately and contains no redundant information. It earns a high score for being appropriately sized and front-loaded.

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 tool's moderate complexity (nested budget object, optional device, output schema present), the description is minimal. It does not explain when to use it compared to siblings, nor does it clarify the semantics of the budget fields beyond what the schema provides. The output schema exists, so return values are covered, but the lack of usage guidance leaves the description somewhat incomplete for guiding an agent toward correct invocation in context.

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 67%: url and device have descriptions, but the budget object itself lacks a description at the top level. The inner properties are described, so the schema partially covers the main parameter. The description adds no additional meaning about how to structure the budget or interpret thresholds, leaving the agent to rely on the schema's inner property descriptions, which are adequate but not enriched.

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's function: checking website performance against budget thresholds. It uses a specific verb ('check') and resource ('website performance'), and the notion of 'budget thresholds' distinguishes it from sibling tools that return raw scores or metrics. However, it does not explicitly name an alternative or contrast with similar tools like get_performance_score, so it is clear but not strongly differentiated.

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?

There is no guidance on when to use this tool instead of siblings such as run_audit, get_performance_score, or get_core_web_vitals. The description only states what it does, leaving the agent to infer appropriate use. No exclusions, alternatives, or preconditions are provided, so usage context is entirely absent.

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