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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered and repeating 'Read-only' adds little. What does add value is the disclosure of return content — a post's caption, status, schedule/publication time and platform URL, or an account's details — which is the main thing an agent needs since no output schema exists.

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 sentence that front-loads the core purpose and then qualifies the id format and return payload. Nothing is wasted and nothing important is buried.

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 one required parameter, no output schema, and accurate annotations, the description supplies everything needed to call the tool: what it reads, the id format, and what comes back. It omits error behavior for ids that no longer resolve, which is a minor gap rather than a blocking one.

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 the baseline is 3, but the description goes beyond it by specifying the id's required format ('post:<id>' or 'account:<id>'), a constraint the schema only calls 'An id returned by search.' That format detail is genuinely decision-relevant.

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 ('Read one search result in full') plus the resource and the exact id format it accepts ('post:<id>' or 'account:<id>'). It also names the sibling that produces the input ('by the id search returned'), so an agent can tell it apart from list_recent_posts, get_post_status, and list_accounts 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?

Clearly establishes the usage context: this is the follow-up call for an id obtained from search, and it enumerates the two id shapes it accepts. It stops short of explicitly ruling out overlapped siblings such as get_post_status for status-only lookups, so it lacks the when-not clause that would earn a 5.

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