Leanfare's report

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful context beyond that: prompt ids like PRM-41 are permanent, and apps that support MCP Apps render the result as a card with selectable spans. It says nothing about result size, pagination, or latency for long ranges such as a year.

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 core content is front-loaded, but the first sentence is a long run-on that crams seven report sections plus parenthetical asides into one breath. The enumerations earn some of their place because there is no output schema, yet the phrasing is denser and more cluttered than necessary.

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 carries the job of telling the agent what comes back, and it does so by listing the report's sections and the card rendering. The one-prompt drill-down mode is also covered. Minor gaps remain around result volume and behavior for very long ranges, but the picture is adequate to call the tool correctly.

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 explains app, range, and prompt, including that range and app are dropped when prompt is supplied. The description reinforces the prompt-id format and the override behavior but adds no syntax or constraint information the schema lacks. Baseline 3 is appropriate.

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 names the resource concretely — a report of what Leanfare did for the user's apps over a span of time — and enumerates the sections it returns (token savings, app usage, cost, quality/grades, tokens over time, work by model, last prompts). That is far more specific than a tautology. It only weakly separates itself from siblings such as spend or models, which cover overlapping territory.

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?

It gives an explicit trigger: use it when the user asks what Leanfare saved, how the models did, or for a report. It also states the parameter routing case (give prompt for a single prompt and its parts). It stops short of naming competing siblings like spend or models as alternatives, so the agent must infer when a narrower tool is preferable.

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