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

Annotations already cover readOnly, idempotent and non-destructive, so the bar is lower, and the description still adds real value: deterministic output, free/no account or payment required, a documented 404 unknown_listing failure mode, and the 'listed, never guessed' guarantee about undocumented fields. Minor gap: no pagination/size or latency expectations.

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?

The lead clause 'Everything needed to use one listing' is front-loaded and the closing sentences are crisp, but the core sentence is a long run-on with nested parentheticals that packs its enumeration densely enough to be hard to scan.

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 and 100% schema coverage on inputs, the description carries the return-value burden and does so thoroughly, including error behavior. It is nearly complete for this tool's complexity; only the absence of any sibling disambiguation keeps it from a 5.

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%, so listing_id, agent_id and trace_id are already fully documented in the schema. The description adds no format, constraint, or interaction detail beyond what is there, which is the expected baseline when the schema does the heavy lifting.

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 enumerates exactly what the tool returns for a single listing: ordered how_to_connect steps with call recipes, payment summary, verification template presence, and trust signals. That is a specific resource and scope. It stops short of 5 because it never contrasts itself with the close sibling get_listing or find_agents, so the agent must infer the boundary.

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?

Usage is implied ('Everything needed to use one listing', id from find_agents) rather than stated. There is no explicit when-to-use versus get_listing/search_listings, and no stated preconditions, so the agent gets only a weak routing signal.

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