Errors per day

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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds real behavioral context on top: default ordering (newest day first), the backing route GET /errors/daily, the 1000-day cap, and that results include user counts and links. It does not describe pagination behavior, though the schema's page field covers that.

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 sentences, front-loaded with what the tool returns and its default ordering, then usage, then the one parameter worth calling out. No filler, though the size sentence duplicates schema text and slightly dilutes the otherwise tight structure.

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 seven-parameter, all-optional read tool with rich annotations and full schema coverage, the description supplies what the structured fields cannot: return payload contents, default sort order, and intended analytical use. No output schema exists, and the description adequately previews the shape of results (totals, user counts, links).

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 every parameter is already documented, including the page/size/sort semantics. The description's note 'Set size to the number of days you need (max 1000)' largely restates the schema's own example, adding little new meaning. Baseline 3 is appropriate.

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?

States a specific resource and granularity — 'Daily error totals with affected-user counts and TrackJS links' — plus the underlying endpoint GET /errors/daily, which unambiguously separates it from siblings like list_errors or top_messages. The only gap is that the nearest sibling, errors_by_hour, is never named or contrasted, though 'Daily' implies the distinction.

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?

Explicitly names use cases: 'Use for trends, spotting spikes and comparing before/after a deploy.' That is clear contextual guidance beyond the name. It stops short of exclusions or pointing to alternatives such as errors_by_hour for intra-day analysis, so it falls short of a 5.

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