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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so safety is covered. The description adds genuinely useful context beyond that: the Agency-plan requirement with a concrete 403 failure mode and parity with the /portfolio page, which helps an agent predict both eligibility and output.

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 value proposition, then a parenthetical inventory of what is returned. The enumeration is dense but each item earns its place as return-value disclosure; no filler sentences.

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 parameters and no output schema, the description carries the burden of describing the return contents, which it does thoroughly (KPIs, totals, movers, triage, opportunities), and it also states the plan prerequisite. Nothing an agent needs to decide or call correctly is missing.

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?

The tool takes zero parameters and the input schema is empty, so there is nothing for the description to disambiguate. Baseline for a no-parameter tool is 4.

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?

States a specific verb+resource ('The whole portfolio's health in one call') and enumerates the aggregation content: per-app KPIs, org-wide totals, keyword movers, triage list, and discovered-keyword opportunities. It is clearly differentiated from per-app siblings like sonar_app_overview by operating across the entire portfolio.

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 clear usage context ('for orgs managing many apps') and a hard gate ('Requires an Agency plan (403 on other plans)'). It does not explicitly name the sibling alternatives an agent should prefer for single-app or per-metric queries, so it stops short of full when/when-not routing.

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