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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description goes further by explaining metric semantics that the schema cannot: p50/p95 are defined as 'answered within' bucket edges and empty-result lookups are surfaced. It does not disclose aggregation granularity, result size, or any limits beyond the schema's days maximum.

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?

Front-loaded with the core verb and the returned metrics, followed by a usage example and a chaining instruction; each sentence carries information. The opening enumeration is dense with semicolons and parentheticals, which slightly taxes readability, but nothing is padding given the absence of an output schema.

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, the description correctly carries the return-shape burden by cataloguing the metrics and their meaning, and it closes the loop with a follow-up tool for drill-down. It leaves out aggregation granularity, response size/paging, and how the days window interacts with the reported daily buckets, which keeps it from being fully complete.

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 100%, so the schema already documents sourceId, days (default 30) and workspace. The description only loosely touches parameters ('compare the first and last weeks' implies a window but gives no syntax for days) and says nothing about workspace selection. Baseline 3 applies when the schema does the heavy lifting.

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 a specific verb and resource ('Read a Caliper source over time'), then enumerates the exact payload an agent gets: traces, failures, tool calls, empty lookups, tokens, cost, speed buckets, per-tool shares, documents, and models. It also implicitly distinguishes itself from caliper_traces_list by positioning that sibling as the drill-down for a single day/tool. An agent can tell what this returns without opening a schema.

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?

Gives a concrete use case ('how often is it calling web search and is that changing — compare the first and last weeks and name the day it moved') and names the follow-up tool (caliper_traces_list on that day or tool). It stops short of stating when NOT to use it or how it compares to caliper_flow_performance, so no explicit exclusion is provided.

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