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

Annotations already mark this read-only, and the description adds genuinely new behavior: premium briefing fallback to 'base health/visibility/backlink metrics instead and says so,' plus the cost trait 'never consumes lookups.' No contradiction with readOnlyHint/openWorldHint.

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?

Three tight sentences: the first gives the overview value, the second explains the parameter and premium fallback, and the third clarifies cost. Every sentence adds distinct information and the core purpose is front-loaded.

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?

For a one-parameter briefing tool with an output schema and read-only annotations, the description covers selection, prerequisite, fallback behavior, and cost. There is no obvious missing detail an agent needs to invoke it 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?

With schema_description_coverage at 0%, the description compensates by explaining that 'project_id is a ranking id from list_projects' and by instructing the caller to get it from list_projects first. That is meaningful beyond the raw integer schema but leaves some nuance (e.g., how to obtain the ID from list_projects output) implicit.

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 a single resource ('one project') and specifies the deliverable: 'health, visibility, top movers, and the highest-priority things to fix now.' It is clear that this is a project-level briefing, though it does not explicitly contrast with sibling tools like get_audit_summary or get_ai_visibility.

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 explicit context for when to use the tool ('The briefing for one project') and a hard prerequisite: 'call list_projects first.' It does not name alternatives or exclusions, but the stated precondition and account-state fallback are useful selection guidance.

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