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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the mutation/scope profile is covered. The description adds a useful safety boundary but says nothing about what invocation actually does — whether it immediately begins audio playback, whether membership/upgrade is required, or whether prior progress state affects playback. With a playback tool, that behavioral gap is meaningful.

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?

Four short sentences, front-loaded with the primary trigger, followed by exclusions. No filler or repetition beyond what the three-way negative scope requires.

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 values need not be explained, and annotations plus full parameter coverage handle safety and inputs. The only real gap is that the description never conveys the side effect of starting audio playback or the role of the tap token in resuming progress.

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 baseline is 3. The description only restates the session_id provenance that the schema already documents, and never mentions the optional 'tap' token from keep_progress — so it adds essentially no meaning beyond the structured fields.

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 states a concrete action (play a session) on a concrete resource and anchors the id to its source (find_sessions / create_personal_session), which makes it distinguishable from discovery siblings like find_sessions and from creation siblings like create_personal_session.

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?

Gives explicit positive triggers (user picks a result from find_sessions, or names a session by id) and explicit negative scope (not medical questions, emergencies, crisis, or general meditation chat). An agent can route without inference.

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