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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the return shape {schedule, publishedBy}, Zod re-validation of segments, and a 404 miss case.

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 tight sentences: the action first, then the return/error contract. No filler, nothing repeated from the schema or annotations.

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 single-parameter read with no output schema, the description covers the essential contract: what comes back, that it is re-validated, and the not-found case. It does not mention caching, pagination, or authorization, but none are strongly implied for a hash-keyed lookup.

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% and the schema already documents scheduleHash as '0x + 64 hex sha256'. The description only echoes 'content hash' without adding format or validation detail, 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 (Fetch) and resource (a published RateSchedule) plus the lookup key (content hash), so an agent can tell it retrieves rather than mutates or evaluates. It does not explicitly differentiate itself from the sibling pcc_schedule_publish / pcc_schedule_evaluate tools, but 'published' and the read framing make the role clear.

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?

No statement of when to use this versus pcc_schedule_evaluate or pcc_schedule_publish, and no prerequisites. The only usage signal is implicit in 'by its content hash', which is a mechanical detail rather than routing guidance.

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