get_page_load_breakdown

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

No annotations are provided, so the description carries the behavioral transparency burden. It adds useful context by naming the data source ('probe RUM') and noting the output includes a diagnosis of where page-load time is spent, implying a read-only analytical tool. However, it omits behavior like aggregation window, auth requirements, side effects, or error conditions.

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 front-loaded sentence: it states the source, scope, output phase list, and diagnostic value without filler. Every element earns its place and the key scoping term 'per route' appears near the beginning.

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?

With no output schema and no annotations, this description is moderately informative but incomplete for a 3-parameter diagnostic tool. It lists what the output covers but does not explain route semantics or how this differs from overlapping siblings like get_web_vitals or diagnose_slow_page. The namespace required note also conflicts with the actual schema, leaving an agent slightly unsure about invocation.

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%, and the description adds meaning only to the route parameter by framing the output as 'per route.' Route itself still lacks syntax or value format in both the schema and description. Additionally, the namespace property description says 'required: no default configured' while the schema's required array is empty, creating a confusing signal for the agent.

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 a RUM-based breakdown of Navigation Timing phases per route and lists the concrete phases returned (dns, connect, tls, ttfb, download, etc.). This is specific enough to distinguish it from generic metrics tools, though it does not explicitly name or name-difference siblings like get_web_vitals or diagnose_slow_page.

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 versus alternatives, no mention of prerequisites, and no exclusions. The description says what it returns, but an agent is left to infer when it should be selected over diagnose_slow_page or get_web_vitals.

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