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chrome_page_load_resource_summary

Read-onlyIdempotent

Summarizes URL-level resource requests during Chrome page loads, including overlap, process info, and navigation relation, to identify performance bottlenecks. Use before hotspot 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
end_ts_nsNoOptional raw trace timestamp upper bound in nanoseconds, exclusive. ANDs with any page-load window.
limitNoOptional max rows to return. Defaults to 25 and is capped at 5000. Must be > 0 when set.
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.
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`.
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`.
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.
start_ts_nsNoOptional raw trace timestamp lower bound in nanoseconds. ANDs with any page-load window.
url_groupingNoURL grouping strategy. Defaults to full URL; use without_query to merge signed/nonce query variants of the same endpoint.

Tool Definition Quality

A4.1/5.0
Behavior4/5

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. Description adds value by noting 'detail is not a root-cause claim' and specifying ranking behavior, which are behavioral traits not in annotations.

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?

Single paragraph with front-loaded output fields and usage guidance. No wasted words, though slightly verbose with field enumerations. Efficient but not maximally concise.

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 9 fully-described parameters, no output schema, and complex domain, the description adequately covers purpose, return fields, and usage order. Missing only edge cases or error behavior, but sufficient for selection.

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?

Schema description coverage is 100% (all 9 parameters have detailed descriptions). The tool description adds minimal parameter insight beyond mentioning ranking by max overlap, which correlates to min_overlap_ms. Baseline 3 is appropriate.

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?

Clearly describes a URL-level resource summary tool for page loads/raw windows, listing key output fields like URL key, overlap, slice evidence. Distinguishes from sibling by stating 'Use 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 ordering: 'Use before chrome_page_load_resource_hotspots' and 'rank by max overlap', providing clear context for when to use this tool relative to a sibling. Lacks explicit when-not or broader alternatives.

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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