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

readOnlyHint=true already establishes this is a safe read. The description adds non-obvious behavior beyond that: results are limited to team-shared annotations, and it discloses the content of the returned records (id, category, description, affected page URLs, source) in the absence of an 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?

Front-loaded with the core action, then scope, then return fields. Efficient overall, though the two parenthetical "etc." lists are slightly padded and the return-field sentence could be trimmed.

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 carries the return-value burden and does so adequately by listing the fields returned. The main gap is lack of differentiation from the adjacent get-recent-annotations tool, which an agent choosing between the two would need.

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 date formats, the property id, categoryId, and includeGlobal defaulting are already documented in the schema. The description names category and URLs as returned content but adds no format or usage semantics for the parameters themselves, so the baseline 3 applies.

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 verb and resource ("Get custom annotations") plus scope ("for a date range") and a visibility constraint ("only returns shared annotations visible to the team"). However, it never explicitly distinguishes itself from the sibling get-recent-annotations, leaving the agent to infer the difference between 'custom' and 'recent'.

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: date-range retrieval of shared annotations. It usefully notes that the returned annotation id can be "pass[ed] to update-annotation", which is a real cross-tool pointer, but it offers no explicit when-to-use or when-not-to-use guidance relative to get-recent-annotations.

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