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

Annotations already declare readOnlyHint/idempotent/non-destructive, so the safety profile is covered. The description adds a real behavioral detail beyond that — the article is returned as Markdown — and enumerates the content domains covered, which tells the agent what kind of payload to expect. It does not discuss size or truncation, but the added value is genuine.

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?

Front-loaded with the action and resource ('Get one SendMyCall help article as Markdown'), followed by a topic list that doubles as slug-discovery aid. The enumeration is long but each group maps to real enum clusters, so it earns its space; no filler sentences.

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?

An output schema exists, so return structure needn't be explained, and annotations cover the safety profile. The description supplies the return format and the content inventory, leaving only minor gaps around article size/handling of the enumerated slug errors.

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 slug enum is fully spelled out with all 33 values, so the schema carries the parameter burden. 'Pick the slug from the list' reinforces that the value must come from the enum but adds no format or semantic detail beyond it. 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?

Specific verb ('Get'), specific resource ('one SendMyCall help article'), and it names the return format ('as Markdown') plus the topical scope. Against siblings that are all pricing/rate lookups (get_calling_rate, get_area_pricing), it is unmistakably the documentation-retrieval tool.

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 only routing instruction is 'Pick the slug from the list,' which is invocation mechanics rather than guidance on when to reach for this tool versus the pricing siblings. Usage is implied by the topical list, but there are no explicit when/when-not conditions or named alternatives.

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