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

Annotations already establish readOnly=true/non-destructive, so the description's job is to add what the agent can't infer. It does add real value by warning that the reported share can diverge from the UI's 'Sessions Adopted' and that the tool merges two data sources, but it says nothing about cost, latency, or behavior when the release or project doesn't exist.

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?

Two sentences, front-loaded with what the tool returns, followed by the caveat that matters most. No filler, though the parenthetical about combining APIs is somewhat redundant with the first clause.

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?

An output schema exists and the input schema is fully annotated, so the description only needs to cover the non-obvious semantics - and the UI-vs-API discrepancy note does exactly that. The main omission is sibling differentiation against sentry_sessions_by_release.

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 coverage is 100%, so all eight parameters are already documented, including the statsPeriod default of 1h and the note that 24h blends older releases. The description's statsPeriod advice largely restates the schema, so the baseline of 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+resource: release metadata combined with project session share for a single version, and notes it fuses the release API with sessions-by-release. That distinguishes it reasonably well, but it never names the sibling sentry_sessions_by_release, which is the closest overlap, so the boundary stays implicit.

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?

Gives operational advice ('Use statsPeriod=1h during rollout') but that is parameter usage rather than tool-selection guidance. Nothing says when to call this versus sentry_sessions_by_release or when a plain release lookup is enough.

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