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

Annotations only declare readOnlyHint and openWorldHint; the description adds that the content comes from a named third-party site (thesepticguide.com) and that results include a short answer, cost tables, and cited sources. That gives the agent a sense of provenance and shape without an output schema. It still doesn't note staleness, currency, or failure behavior for unknown topics.

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 sentences, front-loaded with the resource and coverage list, followed by the zero-argument affordance. Every clause carries information; nothing is redundant with the title or schema.

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-optional-parameter read tool with no output schema, the description supplies provenance, content shape, and the no-argument fallback — enough to invoke correctly. The only gap is error/empty-result behavior, which is low-stakes here.

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% and the schema gives an example slug, so the baseline is 3; the description earns above baseline by documenting the omission behavior (no topic returns a topic list), which the schema does not state. It doesn't clarify slug normalization or what happens on a miss.

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 (get) and resource (septic cost guidance) and enumerates the covered subtopics (pumping, inspection, repair, installation, drain field, tank replacement, aerobic systems). Nothing overlaps with the sibling tools get_state_licensing, list_states, or search_septic_companies, so an agent can route unambiguously.

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?

"Call with no topic to list topics" gives an explicit zero-argument behavior that the schema cannot express, which is real usage guidance. It stops short of naming alternatives or exclusions, but the sibling set is clearly disjoint in domain, so the omission is minor.

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