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

Annotations already establish readOnly, non-destructive and closed-world, and the description's 'Read-only' merely restates that. The value-add is the return shape — one entry per session plus a dashboard link — which is real behavioral context given there is no output schema.

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 front-loaded with the payload contents, then the usage question, then the return shape. Nothing is padded, and the only slight redundancy is 'Read-only' against the annotation.

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 sketches the return (one entry per session, dashboard link). It omits any mention of result volume or cost-estimation caveats, but for a two-parameter read tool it is close to sufficient.

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%, with days and repo_id both documented in the schema itself, so the baseline is 3. The description adds no extra semantics for either parameter (e.g. the 90-day ceiling or repo_id format), so it neither compensates nor detracts.

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 specific resource set — per-session agent activity with edits, lines, tokens, model, cost, rationales and top paths — so the agent knows exactly what comes back. It does not, however, contrast itself with close siblings like recall or get_briefing, which is the missing element for 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?

It gives clear triggering questions: 'what happened' or 'what did this cost'. That is a usable when-to-use signal, but there are no exclusions or named alternatives, so it stops short of full routing guidance.

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