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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description's only added nuance is the word 'stored,' hinting at a cached/local collection rather than a live fetch, but it says nothing about paging behavior, freshness, or response shape.

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?

A single short sentence with no filler is structurally clean, but it is terse to the point of under-specification rather than genuinely concise. It is not front-loaded with any actionable content beyond the noun phrase.

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 three-parameter read tool with no output schema, the description should at minimum tie the parameters together (day + channel slug) and place the tool among its many guide-related siblings. As written it leaves the agent to reconstruct the contract from the schema and sibling names alone.

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 both required parameters and the optional 'antes' paging parameter are already documented in the schema, including the YYYY-MM-DD format and the pointer to guia.proximo. The description adds nothing on top, 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?

The description names the resource (TV guide for a channel on a single day) but is a bare noun phrase with no verb, and it does not distinguish itself from near-identical siblings such as get_channel_guide, get_programacao, or list_programacao. An agent can guess the scope, but cannot tell from this text alone which of those siblings to pick.

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?

There is no statement of when to use this tool versus the other guide/programacao tools, and no mention of the prerequisite of first resolving a channel slug from the collection (only implied in the schema). The description offers no routing guidance at all.

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