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

Annotations already declare readOnly and non-destructive, so the description does not need to restate that. The description adds that it lists opportunities 'closing soon', implying some temporal filtering, which is useful context. However, it does not disclose details like pagination behavior or that results are combined across two sources (CanadaBuys and Alberta APC), which could be important for agent expectations. Given the annotations, a 3 is appropriate as it adds minimal but some context.

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?

The description is a single sentence with no filler: 'List CanadaBuys and Alberta APC opportunities closing soon.' It is appropriately sized for a simple listing tool, and the key scoping info (sources and temporal filter) is front-loaded. Every word earns its place, and it is easy to parse quickly.

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?

Given the tool has an output schema (as indicated by context signals), the description doesn't need to explain return values. The schema fully documents parameters, and annotations cover behavior. The description provides the essential purpose and scope. The only minor gap is not explicitly mentioning that it fetches from two sources (CanadaBuys and Alberta APC) as a combined list, but that's implied by the description. For a simple read-only listing tool, this is largely complete.

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 schema provides 100% description coverage for all 5 parameters, each with clear descriptions for days, limit, source, category, and province. The description doesn't add any extra meaning beyond what the schema already has, such as clarifying that 'days' uses today as the reference or that 'source' has specific format ('all', 'federal', 'alberta'). With full schema coverage, the baseline is 3, and the description adds no value beyond the schema.

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 clearly states the resource ('CanadaBuys and Alberta APC opportunities') and the action ('closing soon'), which is specific and distinct from siblings like find_opportunities or search_opportunities. However, it doesn't explicitly differentiate from list_alberta_deadlines or list_upcoming_deadlines, though the mention of specific sources helps. Overall, it's clear but could be more explicit about what distinguishes it from similar listing tools.

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?

The description implies usage for filtering by time to closing, but does not provide explicit guidance on when to use this tool versus siblings like 'find_opportunities' or 'list_alberta_deadlines'. There is no mention of alternatives or exclusions, so an agent might not know if this is the best choice for a general search vs. deadline-specific queries. The brevity leaves usage context to be inferred.

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