update_issue

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

Annotations supply only openWorldHint=true, so the description carries most of the behavioral burden. It usefully discloses the default return shape (slim: iid, title, state, web_url, updated_at) versus full_response=true — but that same detail is already in the `full_response` schema description, so the added value is limited. For a mutation tool it says nothing about permission requirements, reversibility, or side effects of `state_event` closing/reopening.

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?

Four short sentences, front-loaded with the verb+resource, and no padding. Minor redundancy: "Update an issue" and "Change fields on an existing issue" say the same thing twice, and the response-shape sentence is duplicated in the schema.

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?

Adequate for a 15-parameter mutation tool: field coverage lives in the schema and return shape is addressed. However, with no output schema and no annotation coverage of safety/permissions, the description should say more about the consequences of state transitions and what the slim confirmation actually omits.

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 one of the 15 parameters is already documented (enums for state_event and issue_type, date format for due_date, JMESPath filtering). The description adds no meaning beyond what the schema provides, 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+resource ("Update an issue" / "Change fields on an existing issue") that an agent can match to intent immediately. It also distinguishes two nearby siblings, but only partially — it never contrasts with other write tools in the set (update_merge_request, create_issue) or clarifies that it cannot create issues.

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 routes the agent away from this tool for two cases: targeted description edits go to `update_issue_description_patch`, and discussion goes to `create_issue_note`. There is no when-not-to-use guidance for the broader class of writes (e.g., creating an issue, updating an MR), which keeps it below a 5.

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