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

Annotations only declare readOnlyHint=true, so safety is covered elsewhere. The description adds genuinely non-obvious behavior: a set guide overrides the default craft rules, and the tool returns a note rather than failing when no guide is set — both useful for correct downstream handling. It stops short of stating what the guide payload looks like structurally, but the empty-state and precedence semantics are the important disclosures.

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 with zero filler: purpose first, then concrete channel examples, then the precedence rule, then the empty-state behavior. Every sentence carries information an agent would otherwise have to guess.

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, the description bears the return-value burden and handles the most consequential case (no guide set returns a note) plus how the result should be applied. That is adequate for a simple two-parameter read, though it does not describe what a populated guide contains.

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 the baseline is 3 even though the description also explains channel values. It clarifies 'linkedin_dm' and 'email' with concrete use cases, which is value-add, but it omits the third enum value ('linkedin_comment') and says nothing about on_behalf_of beyond what the schema already states.

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 and resource ('Return the user's writing style guide') plus the scope constraint ('for one channel') and the downstream purpose ('to follow when drafting that channel's outreach'). This resource is distinct from adjacent siblings like get_personalization_guide and get_skill_guide, so an agent can tell them apart without opening a 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?

The description establishes clear context — call this before drafting a channel's outreach and use the returned guide as the user's voice. It does not state exclusions or explicitly route to the related guide tools (get_personalization_guide, get_skill_guide), leaving that comparison to inference.

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