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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds value beyond that by disclosing the shape of what is returned in each of the two modes. It doesn't cover behavior when the issue or event id doesn't resolve, or whether daily counts are bounded.

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 the default behavior before the alternative mode, and every sentence carries information. The trailing field enumeration is dense and slightly awkward ("the request and the person and session ids") but not wasteful.

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 four-parameter read tool with no output schema, the description does the heavy lifting by listing the returned fields in both modes, which is exactly the gap an output schema would otherwise fill. It falls short only on the unexplained issueId and on failure/not-found behavior.

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?

With 75% schema coverage the baseline would be 3, but the description genuinely adds meaning for eventId (it switches the whole read mode, and the id must be sourced from the events list) rather than restating the schema. issueId remains semantically unexplained in both schema and description, which holds it below 5.

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 (read one error issue) and enumerates exactly what comes back (title, culprit, level, status, first/last seen, daily counts, releases, tags). It also carves out the second mode via eventId, so an agent can distinguish it from list_errors or update_error_status without opening the 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?

It states an explicit conditional: pass eventId to read a single occurrence instead of the issue summary, and tells where occurrence ids come from (the issue's events list). What's missing is an explicit when-to-use-this-vs-list_errors boundary, so it's clear context rather than full routing.

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