Project briefing

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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, openWorldHint=false), so the bar is lower; the description still adds real value by disclosing the aggregate return shape and the dual behavior of listing all projects when the name is omitted. It does not mention rate limits, result caps, or pagination, so it is not exhaustive.

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?

Two dense sentences, zero filler, with the aggregation scope front-loaded and the list-all fallback stated last where it belongs.

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 usefully enumerates the returned sections and covers the zero-argument listing mode, which is what an agent needs to call it correctly. The one gap is the unexplained recent_days window, which affects how results are scoped.

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 coverage is only 50%: 'project' is documented in the schema, but 'recent_days' carries no description and the tool description never names it or explains the 30-day default / 1-365 range. 'What changed recently' hints at the recency window but does not compensate for the undocumented parameter.

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?

Names a specific verb and resource ('One-call briefing on a project') and enumerates what the briefing contains (notes by type, progress, decisions, recent changes), which implicitly separates it from single-purpose siblings like brain_read or brain_recent. It never names an alternative sibling explicitly, so it stops short of a 5.

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?

'Call this before discussing any project' is an explicit, actionable when-to-use trigger, and the omit-the-name mode is spelled out. There is no when-not guidance or named alternative for narrower needs (e.g. when brain_search is preferable), so it is clear context without exclusions.

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