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chrome_page_load_resource_summary

Read-onlyIdempotent

Summarizes Chrome resource requests per URL within a page-load window, returning overlap metrics and slice evidence to identify resource bottlenecks before deeper analysis.

Instructions

URL-level Chrome resource/request summary for a page-load/raw window. Returns URL key, process/machine/priority sets, span, max/summed overlap, primary/detail slice evidence (detail is not a root-cause claim), navigation/renderer relation including target_renderer_source, example_slice_id, incomplete_duration_slice_count. Use before chrome_page_load_resource_hotspots; rank by max overlap.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
limitNoOptional max rows to return. Defaults to 25 and is capped at 5000. Must be > 0 when set.
phaseNoOptional page-load phase window. If set without `page_load_id` or `navigation_id`, uses the latest page load in the trace. Values: navigation_to_fcp, navigation_to_load, dcl_to_fcp, fcp_to_load.
trace_idNoOptional trace id returned by `load_trace`. Omit to use the active trace.
end_ts_nsNoOptional raw trace timestamp upper bound in nanoseconds, exclusive. ANDs with any page-load window.
start_ts_nsNoOptional raw trace timestamp lower bound in nanoseconds. ANDs with any page-load window.
page_load_idNoOptional page-load id used to scope resources to one navigation phase. Matches `chrome_page_loads.id`. Mutually exclusive with `navigation_id`. If set without `phase`, defaults to `navigation_to_fcp`.
url_groupingNoURL grouping strategy. Defaults to full URL; use without_query to merge signed/nonce query variants of the same endpoint.
navigation_idNoOptional Chrome navigation id used to scope resources to one navigation phase. Matches `chrome_page_loads.navigation_id`. Mutually exclusive with `page_load_id`. If set without `phase`, defaults to `navigation_to_fcp`.
max_string_lenNoOptional per-string-cell character cap applied to returned rows only. Unset preserves full strings for precision; accepts both numbers and numeric strings. Must be > 0 when set.
min_overlap_msNoOptional minimum per-URL max overlap in milliseconds. Defaults to 50 ms.

Tool Definition Quality

A4.1/5.0
Behavior4/5

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

Annotations already provide readOnlyHint, idempotentHint, non-destructive. Description adds behavioral context: lists output fields, clarifies 'detail is not a root-cause claim', explains navigation/renderer relation. It goes beyond annotations but could mention more about result interpretation or caveats.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Description is moderately sized (3 sentences) and front-loaded with purpose. Could slightly improve structure (e.g., list fields separately), but effectively conveys essential information without redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 10 parameters, no output schema, and annotations covering safety, the description is fairly complete. It lists output fields and usage hints. However, without output schema, it could elaborate on fields like max/summed overlap and incomplete_duration_slice_count.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Input schema has 100% parameter description coverage, so the description does not need to add parameter meaning. It does not provide additional context beyond the schema, maintaining baseline score.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description clearly states it provides a URL-level resource summary for a page-load or raw window, using specific verbs and resource. It distinguishes itself from siblings by noting it should be used before chrome_page_load_resource_hotspots.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly states 'Use before chrome_page_load_resource_hotspots; rank by max overlap', giving clear ordering guidance. However, it does not detail when to avoid this tool or contrast with other similar tools like chrome_page_load_summary.

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

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