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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds real context beyond that: the access-control scope (own/public/unlisted) and the password requirement for protected pastes. It does not say what happens on a wrong password or an inaccessible slug, which keeps it from a 5.

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?

Three short sentences, front-loaded with the core action and return content, then access scope, then the password case. No filler or repetition that isn't doing work.

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 two-parameter read tool with full annotation coverage and no output schema, the description covers action, access scope and the conditional password case, plus a note that content is returned. Missing only failure-mode behavior (not found, wrong password), which is a modest gap.

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 both parameters are already documented, including the slug/link dual format and the password usage. The description only restates those facts ("by slug or pastes.io link", "Supply password") without adding format or edge-case meaning. Baseline 3 applies when the schema carries the parameter semantics.

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 ("Read a paste") and narrows scope to slug/link lookup, which implicitly separates it from list_pastes. It never names a sibling or explicitly says how it differs from create_paste/delete_paste, so differentiation is inferable rather than stated.

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?

"Works for any paste the account can view: its own pastes and public or unlisted ones" gives clear applicability, and "Supply password for a password-protected paste" states the prerequisite for the protected case. There is no explicit when-not or named alternative, so it stops short of a 5.

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