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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the description's job is lighter and it delivers: it discloses the aggregation contents (totals, new, resolved, most frequent errors, hourly rate) that an agent wouldn't otherwise know since there is no output schema. It does not mention pagination or result-size limits, but for a read-only stats call that is a modest gap.

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 sentence, front-loaded with the action and immediately followed by the enumeration of returned metrics. Zero filler.

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-optional-parameter read-only tool with full schema coverage and safety annotations, the description covers what an agent needs: what comes back and over which periods. Missing only a note on default behavior (period defaults to 24h) and whether results are scoped to a project by default.

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%, so the baseline is 3. The description restates the period enum values already in the schema and adds no semantics for projectId or for how period interacts with the returned hourly bucket granularity.

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 verb+resource ('Returns error statistics') and enumerates the contents: totals, new/resolved counts, top errors and hourly rate across three periods. That clearly separates it from list-style siblings like runheed_get_recent or runheed_search_errors, though it never names an alternative explicitly.

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?

Usage is only implied: 'trends' over 24h/7d/30d suggests an aggregate/analytics call rather than a raw error fetch. There is no statement of when to prefer this over runheed_get_recent or runheed_get_project_health, and no prerequisites or exclusions.

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