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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context by disclosing what the returned slots contain (statuses, kind, source, linked article ids) — valuable since there is no output schema. It does not mention scoping/auth requirements for project_id, which keeps it from a 5.

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?

A single compact line with zero filler, front-loaded with the resource and scope, then the returned facets. It is efficient, though the fragment style (colon list, no verb) makes it read more like a schema note than an instruction.

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 two-parameter read tool fully covered by annotations, the description gives enough to call it correctly, and field enumeration partially substitutes for the missing output schema. It stops short of describing the return shape (array vs. keyed-by-date structure), ordering, or whether empty months return nothing.

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%: month is documented as YYYY-MM with a current-month default, and project_id as id or slug. The description's phrase 'for a month' restates the month parameter but adds no format or default detail, and it says nothing about project scoping. Baseline 3 applies when the schema carries the parameter burden.

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 (calendar slots) and its scope (a month) and enumerates the fields each slot carries: status (planned/writing/completed/failed), kind (create/optimize), source (manual/autopilot), and linked article ids. It lacks a verb ('get'/'list') and is written as a telegraphic fragment, but an agent can still tell exactly what data comes back, and no sibling tool covers a calendar.

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?

There is no explicit statement of when to call this versus alternatives, no prerequisites, and no guidance on the relationship to list_articles or get_project. Usage is only implied by the word 'calendar' and the month scope.

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