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

Annotations cover the read-only/idempotent profile, and the description still adds the auth requirement ('Requires the read scope or higher'), the field-level semantics of the return payload, and an important caveat that a missing field is 'no evidence, not none, normal or a clean exit.' It also flags `untrusted_fields` as data LastPing did not write -- meaningful context not present in structured data.

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?

Purpose and auth are front-loaded, but the body collapses into a dense run-on field reference spanning failure_signature, exit_code, duration_vs_normal, cause and untrusted_fields with little structural separation. Length is partly justified by the absent output schema, but readability suffers.

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?

With no output schema and only two params, the description carries the return-value burden thoroughly: ordering, per-field meaning, numeric codes (137 vs 1), sample sizes, and cause categories are all explained. An agent has enough to interpret results correctly.

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% with both parameters fully documented, including defaults and max. The description only echoes this ('an agent's failure inbox', 'newest first') without adding format or syntax beyond the schema, 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?

Opens with a concrete verb+resource and precise scope: 'Returns an agent's failure inbox: every open incident on the monitors it owns, newest first.' The 'open' qualifier implicitly separates it from list_incidents, though no sibling is named explicitly, keeping it short of a 5.

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?

'For learning, at a run's start, what broke meanwhile' gives a clear usage context and timing. It stops short of naming alternatives (list_incidents, get_incident) or stating when not to use it, so no exclusions are provided.

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