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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds real value beyond that: it explains grouping semantics, enumerates the returned group fields, and discloses the legacy groupKey acceptance/ambiguity rule. Pagination behavior is left to the schema, keeping it just short of 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?

The grouping definition and the list_bugs routing are front-loaded, and the field list is informative rather than filler. The single dense paragraph is slightly packed but every sentence carries operational meaning.

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 12-parameter, zero-required read tool with no output schema, the description covers grouping logic, returned fields, and the legacy-key edge case. It is complete enough to call correctly; only minor items like pagination/ordering behavior are left implicit.

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 schema already documents all 12 parameters including enums and defaults; baseline 3 applies. The description adds cross-tool meaning for projectId/groupKey (groupRefs format, legacy key caveats) but does not enrich sort/limit/status semantics beyond what the schema provides.

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 (grouped triage view of bugs collapsed by error signature) and explicitly contrasts it with list_bugs. An agent can distinguish this from list_bugs and the get_bug* siblings without opening either schema.

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?

Names the alternative explicitly ('Prefer this over list_bugs for triage') and gives the condition that selects it. It also explains the cross-tool handoff (pass projectId + groupKey as one groupRefs entry to bulk_update_bugs).

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