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

Annotations already declare readOnlyHint=true, and the description reinforces this with an explicit 'Read-only' note while adding real behavioral detail: the qualifying criteria, the per-item shape (plain-language sentence, canMerge, canArm, merge/arm endpoints), and the auxiliary `waiting_on_you` and `not_ready` sections. That is substantial context beyond what the annotation conveys.

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 qualifying predicate is front-loaded and every clause carries information; the scope and follow-up actions are appended efficiently. The main predicate sentence is a long run-on, but trimming it would lose qualifying criteria, so the density is justified.

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?

There is no output schema, so the description must describe returns — and it does, covering the per-PR payload fields, the human-readable sentence, and the two auxiliary lists. Combined with the scope rules and action pointers, an agent has everything needed to call it and interpret the result.

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 the baseline is 3; the description adds the important combination semantics — owner+repo for a single repository, org for an organisation, and neither for every repository you can merge in — the last of which the schema does not express. It largely restates the per-parameter meanings already in the schema, which keeps it from a 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 gives a precise verb-plus-resource with an exact predicate: open, non-draft PRs with green head CI, no failing/running gates, no standing change requests, protection satisfied, no conflicts, and auto-merge not armed. That definition is specific enough to separate it from gluecron_list_prs, gluecron_pr_status_summary, and gluecron_search_prs without opening any 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 the scope rules (owner+repo, org, or neither) and routes the agent to the follow-up actions gluecron_set_auto_merge and gluecron_merge_pr, plus points to `not_ready` for non-qualifying PRs. It does not explicitly say when to prefer gluecron_list_prs or gluecron_search_prs instead, so it falls just short of naming an exclusion.

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